Question 1

A soccer ball of mass $$0.5\ \mathrm{kg} is $$kicked and its velocity changes from $$2\ \mathrm{m/s} to$$ $$8\ \mathrm{m/s} in$$ $$0.2\ \mathrm{s}. $$What is the magnitude of the impulse delivered to the ball?

Accepted Answer

$$3.0\ \mathrm{kg\cdot m/s}$$

Question 2

Which of the following best describes the law of conservation of linear momentum?

Accepted Answer

The total linear momentum of a system remains constant if no external force acts on it.

Question 3

A $$2\ \mathrm{kg}$$ object moving at $$5\ \mathrm{m/s}$$ collides elastically with a stationary $$3\ \mathrm{kg}$$ object. What is the velocity of the $$2\ \mathrm{kg}$$ object after the collision?

Accepted Answer

$$1\ \mathrm{m/s}$$

Question 4

Which equation correctly relates impulse $$J to $$the change in linear momentum $$\Delta p$$?

Accepted Answer

$$J = \Delta p$$

Question 5

A $$0.2\ \mathrm{kg}$$ ball is dropped from a height of $$10\ \mathrm{m}. $$What is its velocity just before hitting the ground? (Ignore air resistance, $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$14\ \mathrm{m/s}$$

Question 6

Which of the following is the correct formula for kinetic energy?

Accepted Answer

$$KE = \frac{1}{2} m v^2$

Question 7

A $$5\ \mathrm{kg}$$ box is pushed with a force of $$20\ \mathrm{N}$$ over a distance of $$3\ \mathrm{m} at an $$angle of $$0^\circ to $$the direction of motion. What is the work done on the box?

Accepted Answer

$$60\ \mathrm{J}$$

Question 8

Which statement best describes the Work-Energy Theorem?

Accepted Answer

The net work done on an object is equal to its change in kinetic energy.

Question 9

A machine uses $$500\ \mathrm{J} of $$energy to lift a $$40\ \mathrm{kg}$$ box to a height of $$1\ \mathrm{m}. $$What is the efficiency of the machine?

Accepted Answer

$$78.4\%$$

Question 10

Which of the following is the correct formula for gravitational potential energy?

Accepted Answer

$$GPE = m g h$$

Question 11

A $$2\ \mathrm{kg}$$ object is moving in a circle of radius $$0.5\ \mathrm{m} at a $$speed of $$4\ \mathrm{m/s}. $$What is its angular momentum?

Accepted Answer

$$8\ \mathrm{kg\cdot m^2$/s}$$

Question 12

Which of the following best describes the universal law of gravitation?

Accepted Answer

Every object attracts every other object with a force proportional to their masses and inversely proportional to the square of the distance between them.

Question 13

A $$10\ \mathrm{kg}$$ object is lifted vertically $$2\ \mathrm{m} at $$constant speed. What is the work done against gravity?

Accepted Answer

$$196\ \mathrm{J}$$

Question 14

Which formula gives the torque $$	au$$ produced by a force $$F$$ applied at a distance $$r$$ from the axis of rotation?

Accepted Answer

$$	au = F r$$

Question 15

A $$0.5\ \mathrm{kg}$$ ball is thrown horizontally from a $$20\ \mathrm{m}$$ high cliff. How long does it take to hit the ground? ($$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$2.02\ \mathrm{s}$$

Question 16

Which of the following is the correct expression for total mechanical energy?

Accepted Answer

$$E_{mech} = KE + GPE$$

Question 17

A $$3\ \mathrm{kg}$$ object moving at $$6\ \mathrm{m/s}$$ collides inelastically with a $$2\ \mathrm{kg}$$ object at rest. What is their final velocity after collision?

Accepted Answer

$$3.6\ \mathrm{m/s}$$

Question 18

Which of the following is the correct formula for angular acceleration $$\alpha$$?

Accepted Answer

$$\alpha = \frac{	au}{I}$$

Question 19

A $$0.3\ \mathrm{kg}$$ object moves in a circle of radius $$0.4\ \mathrm{m} at$$ $$3\ \mathrm{m/s}. $$What is the centripetal force acting on it?

Accepted Answer

$$6.75\ \mathrm{N}$$

Question 20

Which of the following best describes the conservation law of angular momentum?

Accepted Answer

The total angular momentum of a system remains constant if no external torque acts on it.

Physics Exam 2 Study Guide: Mechanics, Energy, and Momentum

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