Question 1

A 20 N horizontal force is applied to a 4.0 kg box. Friction is negligible. The box moves a horizontal distance of 3.0 meters. What is the work done by the 20 N force?

Accepted Answer

$$60 \ \mathrm{J}$$

Question 2

A 30.0 kg box slides up a 12.0 meter long incline at an angle of $$30.0^\circ$$ above the horizontal. Friction is negligible. What is the change in gravitational potential energy?

Accepted Answer

$$2190 \ \mathrm{J}$$

Question 3

A 5.00 gram bullet has a velocity of $$300 \ \mathrm{m/s}. It $$strikes a block of wood and penetrates to a distance of $$10.0 \ \mathrm{cm}. $$What is the average force of the block of wood on the bullet?

Accepted Answer

$$2,250 \ \mathrm{N}$$

Question 4

A 20.0 kg box slides up a 12.0 m long incline at an angle of $$30.0^\circ$$ with the horizontal. A force of 150 N is applied to the box to pull it up the incline. The applied force makes an angle of $$10.0^\circ to $$the incline and above the incline. If the incline has a coefficient of kinetic friction of $$0.100$$, then the increase in the kinetic energy of the box is:

Accepted Answer

$$241 \ \mathrm{J}$$

Question 5

A 120 N force is applied at an angle of $$30.0^\circ$$ above the horizontal to a 4.00 kg box. The box moves a horizontal distance of $$6.00 \ \mathrm{m}. $$What is the change in the kinetic energy of the box?

Accepted Answer

$$750 \ \mathrm{J}$$

Question 6

A 75.0 kg skier slides down a $$75.0 \ \mathrm{m}$$ high slope without friction. What is the velocity of the skier at the bottom of the slope?

Accepted Answer

$$38.3 \ \mathrm{m/s}$$

Question 7

A spring with a spring constant of $$8.0 \ \mathrm{N/m} is $$initially compressed $$5.0 \ \mathrm{cm}. $$The work done as it is compressed another $$15 \ \mathrm{cm}$$, to a total compression of $$20 \ \mathrm{cm}$$, is:

Accepted Answer

$$0.52 \ \mathrm{J}$$

Question 8

A spring-powered dart gun is un-stretched and has a spring constant $$150 \ \mathrm{N/m}. $$The spring is compressed by $$8.00 \ \mathrm{cm}$$ and a $$5.00 \ \mathrm{g}$$ projectile is placed in the gun. What is the maximum height of the projectile when it is shot at an angle of $$30.0^\circ$$ above the horizontal from the gun?

Accepted Answer

$$5.03 \ \mathrm{m}$$

Question 9

A $$90.0 \ \mathrm{kg}$$ person is running up the stairs at $$0.500 \ \mathrm{m/s}. $$What is the power needed to run up the stairs?

Accepted Answer

$$441 \ \mathrm{Watts}$$

Question 10

A $$2.00 \ \mathrm{kg}$$ pendulum bob on a string $$1.50 \ \mathrm{m}$$ long is released with a velocity of $$0.00 \ \mathrm{m/s}$$ when the support string makes an angle of $$60.0^\circ$$ with the vertical. What is the tension in the string at the bottom of the swing?

Accepted Answer

$$56.1 \ \mathrm{N}$$

Physics Study Guide: Work, Energy, Forces, and Motion

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