Question 1

A 720,000 kg locomotive traveling at 120 km/h sees a log on the railroad tracks ahead. The engineer immediately applies the brakes and the locomotive decelerates at $$2.65\ \mathrm{m/s^2$}. $$How far does the locomotive travel before coming to a complete stop?

Accepted Answer

$$209\ \mathrm{m}$$

Question 2

Given the same scenario as above, what is the coefficient of kinetic friction $$\mu_k$$ between the wheels and the track, assuming all braking force is due to friction?

Accepted Answer

$$0.270$$

Question 3

An arrow is shot horizontally from a bow from a height of $$1.5\ \mathrm{m}$$ with a speed of $$12\ \mathrm{m/s}. $$How much time does it take for the arrow to hit the ground?

Accepted Answer

$$0.55\ \mathrm{s}$$

Question 4

For the same arrow, what is the vertical component of the arrow's speed as it hits the ground? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$-5.4\ \mathrm{m/s}$$

Question 5

A child pulls a $$23\ \mathrm{kg}$$ sled at an angle of $$32^\circ$$ above the horizontal on a flat, grass-covered surface. The coefficient of kinetic friction between the sled and grass is $$0.35. $$What is the magnitude of the normal force between the ground and the sled?

Accepted Answer

$$183\ \mathrm{N}$$

Question 6

A $$200\ \mathrm{g}$$ hockey puck initially at rest starts to slide down a metal ramp that is inclined at a $$40^\circ$$ angle. The coefficient of kinetic friction between the puck and the ramp is $$0.30. $$The incline is $$1.8\ \mathrm{m}$$ long. What is the puck's final speed at the bottom of the ramp?

Accepted Answer

$$3.8\ \mathrm{m/s}$$

Question 7

Which of the following is the correct expression for the drag force experienced by an object moving through air, as given in the provided formula sheet?

Accepted Answer

$$D = \frac{1}{2} C_D \rho A v^2$

Question 8

A $$50\ \mathrm{kg}$$ skydiver falls at terminal velocity. If the drag coefficient $$C_D is$$ $$1.0$$, the air density $$\rho is$$ $$1.2\ \mathrm{kg/m^3$}$$, and the cross-sectional area $$A is$$ $$0.7\ \mathrm{m^2$}$$, what is the terminal velocity $$v_t$$? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$42\ \mathrm{m/s}$$

Question 9

A car of mass $$1,200\ \mathrm{kg} is $$moving at $$25\ \mathrm{m/s}$$ when the driver slams on the brakes, causing the car to skid to a stop. If the coefficient of kinetic friction between the tires and the road is $$0.80$$, how far does the car travel before stopping?

Accepted Answer

$$40\ \mathrm{m}$$

Question 10

A $$2.0\ \mathrm{kg}$$ block is pushed up a $$30^\circ$$ incline with an initial speed of $$5.0\ \mathrm{m/s}. $$The coefficient of kinetic friction is $$0.20. $$How far up the incline does the block travel before coming to rest?

Accepted Answer

$$1.1\ \mathrm{m}$$

Question 11

A $$0.5\ \mathrm{kg}$$ ball is thrown vertically upward with an initial speed of $$10\ \mathrm{m/s}. $$Neglecting air resistance, what is the maximum height reached by the ball?

Accepted Answer

$$5.1\ \mathrm{m}$$

Question 12

A $$10\ \mathrm{kg}$$ box is pulled across a horizontal floor with a force of $$50\ \mathrm{N} at an $$angle of $$20^\circ$$ above the horizontal. The coefficient of kinetic friction is $$0.25. $$What is the acceleration of the box?

Accepted Answer

$$2.1\ \mathrm{m/s^2$}$$

Question 13

A $$5.0\ \mathrm{kg}$$ object is acted on by two forces: $$F_1 = 10$$\ \mathrm{N}$$ east and F_2$ = 6\ \mathrm{N}$$ north. What is the magnitude of the object's acceleration?

Accepted Answer

$$2.4\ \mathrm{m/s^2$}$$

Question 14

A $$0.2\ \mathrm{kg}$$ ball is dropped from a height of $$2.0\ \mathrm{m}. $$What is its speed just before hitting the ground? (Neglect air resistance.)

Accepted Answer

$$6.3\ \mathrm{m/s}$$

Question 15

A $$1,000\ \mathrm{kg}$$ car is moving at $$20\ \mathrm{m/s}$$ when it runs out of fuel and coasts to a stop. If the total resistive force (friction and drag) is $$500\ \mathrm{N}$$, how far does the car travel before stopping?

Accepted Answer

$$400\ \mathrm{m}$$

Question 16

A $$0.3\ \mathrm{kg}$$ object is attached to a string and swung in a horizontal circle of radius $$0.5\ \mathrm{m} at a $$speed of $$2.0\ \mathrm{m/s}. $$What is the tension in the string?

Accepted Answer

$$2.4\ \mathrm{N}$$

Question 17

A $$0.5\ \mathrm{kg}$$ block slides down a frictionless incline of $$30^\circ$$ that is $$2.0\ \mathrm{m}$$ long. What is the speed of the block at the bottom?

Accepted Answer

$$4.4\ \mathrm{m/s}$$

Fundamental Mechanics: Kinematics, Forces, and Friction (Physics 201 Exam #1 Study Guide)

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