Q: A disk of mass $$0.50\,\mathrm{kg}$$ and radius $$0.17\,\mathrm{m}$$ rotates at $$2.25\,\mathrm{rad/s}$$ about its central axis. What is its angular momentum $$L$$?

$$2.24 \times 10$$^{-2}$$\,\mathrm{kg\cdot m^2$/s}$$

Q: Which of the following best describes the work done by the applied force when pushing a box up a ramp at an angle $$\theta to $$the horizontal?

$$W = F_{\mathrm{app}} d \cos \theta$$

Question 1

A car of mass $$m is $$moving at a constant velocity $$v on a $$flat road. Suddenly, the driver applies the brakes, and the car comes to a stop after traveling a distance $$d. If $$the coefficient of kinetic friction between the tires and the road is $$\mu_k$$, what is the magnitude of the frictional force acting on the car?

Accepted Answer

$$F = \mu_k m g$$

Question 2

A block is pushed up a frictionless incline with an initial velocity of $$2.0\,\mathrm{m/s}. $$The incline makes an angle $$	heta = 17^\circ$$ with the horizontal. How far up the incline does the block move before coming to rest?

Accepted Answer

$$0.649\,\mathrm{m}$$

Question 3

A stone is launched vertically upward with an initial velocity of $$15\,\mathrm{m/s}. $$What will be the stone's direction of travel after $$2$$ seconds?

Accepted Answer

Downward

Question 4

Which of the following statements about work done by a non-conservative force is correct?

Accepted Answer

It is path dependent.

Question 5

A child’s toy uses a spring with spring constant $$k = 20\,\mathrm{N/m} to $$shoot a block of mass $$0.5\,\mathrm{kg} up a $$ramp inclined at $$30^\circ$$ from the horizontal. The spring is compressed $$5.0\,\mathrm{cm}$$ and released. If the coefficient of kinetic friction is $$0.10$$, what is the net work done by friction as the block moves up the ramp until it comes to rest?

Accepted Answer

$$0.64\,\mathrm{J}$$

Question 6

A disk of mass $$0.50\,\mathrm{kg}$$ and radius $$0.17\,\mathrm{m}$$ rotates at $$2.25\,\mathrm{rad/s}$$ about its central axis. What is its angular momentum $$L$$?

Accepted Answer

$$2.24 	imes 10$$^{-2}$$\,\mathrm{kg\cdot m^2$/s}$$

Question 7

A chicken is running in a circular path with an angular speed of $$1.52\,\mathrm{rad/s}. $$How long does it take the chicken to complete one revolution?

Accepted Answer

$$4.13\,\mathrm{s}$$

Question 8

A woman is practicing yoga and moves from warrior pose 1 into warrior pose 2. How does this affect the pressure her weight exerts on the floor?

Accepted Answer

Decrease in pressure

Question 9

A uniform ball is released from rest on a no-slip surface. After reaching its lowest point, the ball begins to roll up again, this time on a frictionless surface. When the ball reaches its maximum height on the frictionless surface, it is:

Accepted Answer

Lower than when it was released.

Question 10

A brick weighs $$50.0\,\mathrm{N}$$ and measures $$0.30\,\mathrm{m} 	imes 0.10\,\mathrm{m} 	imes 0.40\,\mathrm{m}. $$What is the minimum pressure it can exert on a horizontal surface due to its weight?

Accepted Answer

$$1.25\,\mathrm{Pa}$$

Question 11

A stone is launched horizontally from a volcano with a speed of $$20\,\mathrm{m/s}$$ from a height of $$94\,\mathrm{m}. $$Neglecting air resistance, what is the horizontal displacement from launch point to hitting the ground?

Accepted Answer

$$87\,\mathrm{m}$$

Question 12

A string attached to a stone is swung in a circle with a radius of $$0.5\,\mathrm{m}. If $$the stone's angular acceleration is $$2\,\mathrm{$$rad/s^2$$}$$, what is the tangential acceleration?

Accepted Answer

$$4\,\mathrm{m/s^2$}$$

Question 13

A 2.03 kg book is placed on a flat desk. Suppose the coefficient of static friction between the book and the desk is $$0.442$$ and the coefficient of kinetic friction is $$0.240. $$What is the force of friction on the box when a $$1.5\,\mathrm{N}$$ horizontal push is applied to the box?

Accepted Answer

$$2.48\,\mathrm{N}$$

Question 14

Which of the following best describes the work done by the applied force when pushing a box up a ramp at an angle $$	heta to $$the horizontal?

Accepted Answer

$$W = F_{\mathrm{app}} d \cos 	heta$$

Question 15

Two spinning disks have the same angular momentum, but disk 1 has more kinetic energy than disk 2. Which disk has the greater moment of inertia?

Accepted Answer

Disk 2

Question 16

A playground merry-go-round has a radius of $$2.0\,\mathrm{m}. $$Bonnie applies a force of $$31\,\mathrm{N}$$ tangentially at the edge. What is the magnitude of the torque she inputs to the merry-go-round?

Accepted Answer

$$62\,\mathrm{Nm}$$

Question 17

A vector has components $$A_x = 6$$ units and $$A_y = -10$$ units. What angle does this vector make with the positive x-axis?

Accepted Answer

$$-59^\circ$$

Question 18

The average velocity of an object for a round trip between two locations:

Accepted Answer

Is zero.

Question 19

A diver swims to the bottom of a pool that is $$2\,\mathrm{m}$$ deep. What is the pressure at the bottom of the pool if it is filled with water? (Assume $$ho_{\mathrm{water}} = 1000\,\mathrm{kg/m^3$}$$, $$g = 9.8\,\mathrm{m/s^2$}$$, atmospheric pressure $$= 1.01 	imes 10^5$\,\mathrm{Pa})$$

Accepted Answer

$$121\,\mathrm{kPa}$$

Physics 1401 SI: Cumulative Review Study Guide

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