Five ramps lead from the ground to the second floor of a workshop, as sketched below. All five ramps have the same height; ramps B, C, D and E have the same length; ramp A is longer than the other four. You need to push a heavy cart up to the second floor and you may choose any one of the five ramps.Assuming no frictional forces on the cart, which ramp would require you to do the least work?

Answer:

Explanation:

Summing moments about the CG to zero will show that the two normal forces are equal and have a value of FL = FR = 684/2 = 342 N

Pressure on the left

PL = 342 / 6.20e-4 = 551,612.9032... = 5.5e5 Pa

Pressure on the right

PR = 342 / 9.20e-4 = 371,739.1304... = 3.7e5 Pa

A) The force from the left tire is; FL = 342 N

B) The pressure from the left tire is; PL = 551613 N/m²

C) The force from the right tire is; FR = 342 N

D) The pressure from the right tire is; PR = 371739 N/m²

We see that;

FL and FR are upward forces

W is the downward force.

We know that in equilibrium;

Sum of upward forces = sum of downward forces

Thus;

FL + FR = W

We are given W = 684 N

Since W is at the center, it means that FL = FR. Thus;

FL = FR = 684/2

FL = FR = 342 N

We are given;

Contact area of left tire; AL = 6.2 × 10⁻⁴ m²

Contact area of right tire; AR = 9.2 × 10⁻⁴ m²

Formula for pressure is;

Pressure = Force/Area

Pressure on the left tire;

PL = FL/AL

PL = 342/(6.2 × 10⁻⁴)

PL = 551613 N/m²

Pressure on the t right tire;

PR = FR/AR

PR = 342/(9.2 × 10⁻⁴)

PR = 371739 N/m²

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[tex]\textbf{A}\cdot\textbf{B} = 11.5[/tex]

Explanation:

The dot product between two vectors [tex]\textbf{A}[/tex] and [tex]\textbf{B}[/tex] is defined as

[tex]\textbf{A}\cdot\textbf{B} = AB\cos{\theta}[/tex]

where A and B are the magnitudes of the vectors [tex]\textbf{A}[/tex] and [tex]\textbf{B},[/tex] respectively and [tex]\theta[/tex] is the angle between the two. Since A = 3, B = 5 and [tex]\theta = 40°,[/tex] the dot product [tex]\textbf{A}\cdot\textbf{B}[/tex] is

[tex]\textbf{A}\cdot\textbf{B} = (3)(5)(0.766) = 11.5[/tex]

Answer:

D

Explanation:

Process of elimnination + it's the only one that makes sense

An object will begin moving from rest when acted upon by forces that are greater in one direction than in any other direction. Hence, Option (D) is correct.

The definition of force in physics is: The push or pull on a massed object changes its velocity. An external force is an agent that has the power to alter the resting or moving condition of a body. It has a direction and a magnitude.

When  forces that are greater in one direction than in any other direction, resultant will be  unbalanced forces.  Unbalanced forces are those acting on a body when the net force acting on the body is greater than zero. The body alters its state of motion when unbalanced forces act on it.

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The modern atomic model is called the nuclear atomic model.

Therefore the correct answer is option C.

There are many types of atomic models proposed in past based on their individual assumptions and the experimentations

John Dalton's atomic model.

The Plum Pudding Model, developed by J.J. Thomson,

Rutherford's model provided an explanation for the presence of a nucleus inside the atom.

In accordance with the current atomic model, atoms have a nucleus made up of protons and neutrons and an ethereal gradient or cloud surrounding them that houses electrons;

The modern atomic model is called the nuclear atomic model.

Thus, the correct answer is option C.

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Hi there!

The formula for velocity given acceleration:

v = at

Plug in given values:

v = 6.4(7) = 44.8 m/s

Answer:

M1 + M2 = 0   total momentum before explosion = momentum after explosion where M1 is the lighter fragment

M1 V1 + 7 M1 V2 = 0

V2 = -V1 / 7      

The lighter fragment will slide 7 times as far - 39.2 mm because it must have 7 times as much velocity - assuming the distance slid is proportional to the original velocity

Answer:

15[m].

Explanation:

1) the required distance is AD, for more info see the attached picture.

2) [tex]AD=\sqrt{AA_1^2+A_1D^2} =\sqrt{81+144}=15[m].[/tex]

Answer:

Explanation:

s 0.12 + 1.20(1.80) = 2.28 m from the top.

Answer:

40 volts

Explanation:

Use the equation [tex]V=IR[/tex]

[tex]V=(4)(10)[/tex]

[tex]V=40[/tex]

Answer:it’s C

Explanation:

by using graph of velocity vs. time for two objects, Item 4 and Item 5 statement makes an accurate comparison of the motions for objects. thus option C is correct.

velocity is the  rate of change of the position of the object with respect to  reference and it is complicated but velocity is basically speeding a particular object in a specific direction.

Velocity is a vector quantity which means both magnitude (speed) and direction are combinedly define define velocity. The SI unit of velocity is meter per second (ms-1) and the magnitude or the direction of velocity of a body changes leads to acceleration.

Speed and velocity are the two closest term but the major difference between speed and velocity is that speed gives us an idea that the object with the faster rate of movement r where as  velocity  speed up as well as  tells us the direction of the body

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Answer:

A) 58 km

B) 30 mins

Explanation:

In pic details

graph in pic

Answer:  You need to use Newton's law for the equation --->

Explanation: G  ×  M  ×  m / separation. Thats how youll get your answer !!

Hi there!

We can begin by finding the total time taken for the ball to reach the net using the equation:

dₓ = vₓt

12.9 = 44.7t

12.9/44.7 = t = 0.289 s

Now, we can use the following equation to solve for displacement in the Y direction:

d = y₀ + vit + 1/2at²

There is no initial vertical velocity, so:

d = y₀ + 1/2at²

Plug in known values:

d = 1.28 + 1/2(-9.8)(0.289²)

d = 0.87m

Thus, since 0.87 m < 0.914 m, the tennis ball does NOT make it over the net.

Answer:

In space we feel weightlessness because the earth's gravity has less effect on us. The Earth's gravitational attraction at those altitudes is only about 11% less than it is at the Earth's surface. If you had a ladder that could reach as high as the shuttle's orbit, your weight would be 11% less at the top.

Explanation:

Hope this helps:)

Answer:

0.067 births per chipmunk per year

Explanation:

I took the test

Hi there!

We know that:

I = Δp = m(vf - vi)

Plug in the given values. Remember to take into account direction ⇒ let the rebound velocity be positive and initial be negative.

I = 1.1(5 - (-23)) = 30.8 Ns

Explanation:

Since the neutron is only moving at 1000 m/s, we are going to ignore the relativistic effects on its mass and energy. The mass of a neutron in [tex]m_n = 1.67×10^{-27}\:\text{kg}[/tex] so its kinetic energy KE is

[tex]KE = \frac{1}{2}m_nv^2[/tex]

[tex]\:\:\:\:\:\:\:\:= \frac{1}{2}(1.67×10^{-27}\:\text{kg})(10^3\:\text{m/s})^2[/tex]

[tex]\:\:\:\:\:\:\:\:= 8.35×10^{-22}\:\text{J}[/tex]

A photon's energy E is defined as

[tex]E = h\nu[/tex]

where [tex]\nu[/tex] is the photon's frequency and h is the Planck's constant. Solving for the frequency, we get

[tex]\nu = \dfrac{E}{h} = \dfrac{8.35×10^{-22}\:\text{J}}{6.63×10^{-34}\:\text{J-s}}[/tex]

[tex]\:\:\:\:\: = 1.26×10^{12}\:\text{Hz}[/tex]

which is right around the infrared radiation range.

Answer:

The distance traveled before takeoff is 1720 m

Explanation:

a = + 3.2 m/s²

t = 32.8 s

Vᵢ = 0 m/s

d = ?

Now,

d = Vᵢ × t + 0.5 × a × t²

d = (0 m/s) × (32.8 s) + 0.5 × (3.20 m/s²) × (32.8 s)²

d = 1720 m

Thus, The distance traveled before takeoff is 1720 m

-TheUnknownScientist 72

Explanation:

The orbiting period of a satellite at a height h from earth' surface is

T=2πr32gR2

where r=R+h.

Then, T=2π(R+h)R(R+hg)−−−−−−−−√

Here, R=6400km,h=1600km=R/4

T=2πR+R4−−−−−−√R(R+R4g)−−−−−−−−−⎷=2π(1.25)32Rg−−√

Putting the given values,

T=2×3.14×(6.4×106m9.8ms−2)−−−−−−−−−−−−√(1.25)32=7092s=1.97h

Now, a satellite will appear stationary in the sky over a point on the earth's equator if its period of revolution around the earthh is equal to the period of revolution of the earth up around its own axis whichh is 24h. Let us find the height h of such a satellite above the earth's suface in terms of the earth,'s radius.

Let it be nR.Then

T=2π(R+nR)R(R+nRg)−−−−−−−−−−√

=2π(Rg)−−−−−√(1+n)32

=2×3.14(6.4×106m/s9.8m/s2)−−−−−−−−−−−−−−−⎷(1+n)32

(5075s)(1+n)32=(1.41h)(1+n)32

For T=24h, we have (24h)=(1.41h)(1+n)32

or (1+n)32=241.41=17

or 1+n(17)23=6.61

or n=5.61

The height of the geostationary satellite above the earth's surface is nR=5.61×6400km=6.59×104km.

Answer:

Remember, NORTH ^, EAST >, SOUTH v, WEST <

Explanation:

It doesn't have to be a super complex answer. All you have to do is look to the left (west) of the North American plate. What are the 2 plates that you see? The Pacific and the Juan de Fuca, yeah? To the South, there is the Cocos amongst a few others.

I am not going to share the answer for sure as I haven't completed the test yet but that's how I'm solving it. You should write the answer in your own words anyways. Hope this helps! Have a good day :)

Answer:

The Juan de Fuca Plate and the Pacific Plate both border the west side of the North American Plate.

Explanation:

Edmentum

Explanation:

The initial kinetic energy [tex]KE_0[/tex] is

[tex]KE_0 = \frac{1}{2}mv_0^2 = \frac{1}{2}(400\:\text{kg})(10\:\text{m/s})^2[/tex]

[tex]\:\:\:\:\:\;\:= 2×10^4\:\text{J} = 20\:\text{kJ}[/tex]

The final kinetic energy [tex]KE[/tex] is

[tex]KE = \frac{1}{2}mv^2 = \frac{1}{2}(400\:\text{kg})(30\:\text{m/s})^2[/tex]

[tex]\:\:\:\:\:\:\:= 1.8×10^5\:\text{J} = 180\:\text{kJ}[/tex]

The work done W on the car is

[tex]W = \Delta{KE} = KE - KE_0[/tex]

[tex]\:\:\:\:\:\:\:= 180\:\text{kJ} - 20\:\text{kJ} = 1.6×10^5\:\text{J}[/tex]

The power expended P is

[tex]P = \dfrac{W}{t} = \dfrac{1.6×10^5\:\text{J}}{15\:\text{s}} = 10667\:\text{Watts}[/tex]

[tex]\:\:\:\:\:= 10.7\:\text{kW}[/tex]

Hi there!

We can use the equation:

d = v₀t + 1/2at²

Where:

v₀ = initial velocity downward

a = acceleration due to gravity

t = time

Plug in given values:

d = 4(12) + 1/2(9.8)(12²)

d = 48 + 705.6 = 753.6 m

The applied torque increases the angular speed by the application of an

angular acceleration.

Reasons:

The speed of the flywheel at the axis = 4 rev/s

The torque applied, T = 25 N·m

The time the torque is applied, t = 10 sec

Moment of inertia of the flywheel, I = 1.2 kg·m²

Required:

The speed at the end of the 10 seconds

Solution:

T = I·α

Where;

α = Angular acceleration

[tex]\displaystyle \alpha = \frac{T}{I}[/tex]

Therefore;

[tex]\displaystyle \alpha = \frac{24 \ N\cdot m}{1.2 \ kg \cdot m^2} = \mathbf{20\frac{5}{6} \ s^{-2}}[/tex]

The rotational speed, ω = ω₀ + α·t

Which gives;

[tex]\displaystyle \mathrm{The \ angular \ speed, } \ \omega = \frac{2 \cdot \pi \times 4 \ rad }{s} = \frac{8 \cdot \pi \ rad }{s}[/tex]

ω₀ = 8·π rad/s

Which gives;

[tex]\displaystyle \omega = \mathbf{8 \cdot \pi +2 \frac{5}{6} \times 10} = 233.47[/tex]

The speed of the wheel in revolution per second is therefore;

[tex]\displaystyle Speed \ in \ rev/s = \frac{8 \cdot \pi +2 \frac{5}{6} \times 10}{2\cdot \pi} \approx 37.16[/tex]

The speed after 10 seconds is approximately 37.16 rev/s.

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11.4 m/s

Explanation:

The cord will break when the centripetal force exerted on it meets or exceeds the maximum tension [tex]T_{max}[/tex] that it can handle.

[tex]T_{max} = m\dfrac{v_{max}^2}{r}[/tex]

Solving for [tex]v_{max},[/tex] we get

[tex]v_{max}^2 = \dfrac{rT_{max}}{m}[/tex]

or

[tex]v_{max} = \sqrt{\dfrac{rT_{max}}{m}} =\sqrt{\dfrac{(1.3\:\text{m})(60\:\text{N})}{(0.6\:\text{kg})}}[/tex]

[tex]\:\:\:\:\:= 11.4\:\text{m/s}[/tex]

Answer:

Explanation:

Normal force of the surface on the box will be

N = mg - Fsinθ

Ν = 10(9.8) - 600sin37

N = -263

As normal force cannot be less than zero, the applied force lifts the crate off the surface.

Now it's just a matter of finding the acceleration

In the horizontal direction, the acceleration is

a = F/m

a = (600cos37) / 10

a =  47.9181... m/s²

the crate weight is mg = 10(9.8) = 98 N.

In the vertical direction the acceleration is

a = ((600sin37 - 98) / 10)

a = 26.3089... m/s²

total acceleration is

a = √(47.9181² + 26.3089²)

a = 54.6653... m/s²

s = ½at²

t = √(2s/a)

t = √(2(1.0)/54.6653)

t = 0.19127...

t = 0.19 s

Answer:

not sure i need points

Explanation: