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3 years ago

9

Driving at 75m/s, you hit the brakes on your new car, accelerating at a rate of -20m/s. How long will it take the car to come to

rest?

1 answer:

soldi70 [24.7K]3 years ago

5 0

Answer:

3.75s

Explanation:

Using equation of motion, t= (v-u)/a

where v=0, u=75 and a=-20

t=-75/-20=75/20=3 /.75

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if you were floating in the solar system at equal distances between mars (small mass) and jupiter (large mass) which planet woul

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You would gravitate towards Jupiter because if it’s large mass it has a stronger gravitational pull

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A skier is pulled by a towrope up a frictionless ski slope that makes an angle of 12 degrees with the horizontal. The rope moves

MArishka [77]

Answer:

Explanation:

Given,

Work done by the rope 900 m/s.
Angle of inclination of the slope = $\theta\ =\ 12^o$
Initial speed of the skier = v = 1.0 m/s
Length of the inclined surface = d = 8.0 m

part (a)

The rope is doing the work against the gravity on the skier to uplift up to the inclined surface. Therefore the work done by the rope is equal to the work done on the skier due to the gravity

$\therefore W_r\ =\ W_g\ =\ 900\ J$

In both cases the height attained by the skier is equal. and the work done by gravity does not depend upon the speed of the skier.

part (b)

Initial speed of the skier = v = 1.0 m/s.

Rate of the work done by the rope is power of the rope.

$Power\ =\ \dfrac{\Delta W}{\Delta t}\\\Rightarrow P\ =\ \dfrac{\Delta W}{\dfrac{d}{v}}\\\Rightarrow P\ =\ \dfrac{\Delta W\times v}{d}\\\Rightarrow P\ =\ \dfrac{900\times 1.0}{8.0}\\\Rightarrow P\ =\ 112.5\ Watt$

Part (c)

Initial speed of the skier = v = 2.0 m/s.

Rate of the work done by the rope is power of the rope.

$Power\ =\ \dfrac{\Delta W}{\Delta t}\\\Rightarrow P\ =\ \dfrac{\Delta W}{\dfrac{d}{v}}\\\Rightarrow P\ =\ \dfrac{\Delta W\times v}{d}\\\Rightarrow P\ =\ \dfrac{900\times 2.0}{8.0}\\\Rightarrow P\ =\ 225\ Watt$

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3 years ago

The lift does 3000 J of work in 5 seconds. What is the power of the lift?

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Answer:

600

Explanation:

p=Work/time

3000/5=600 is power

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ly apsamtios ccoriendor sabe r

llpop

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The space shuttle, in circular orbit around the Earth, collides with a small asteroid which ends up in the shuttle's storage bay

Artemon [7]

Answer:

b

Explanation:

The space shuttle, in circular orbit around the Earth, collides with a small asteroid which ends up in the shuttle's storage bay.

This form of collision is called inelastic collision. And inelastic collision momentum is conserved but the kinetic energy is not conserved. Hence the correct option is b. only momentum is conserved.

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