Q: A $$1.43\ \mathrm{kg}$$ hammer head moving at $$3.2\ \mathrm{m/s} is $$stopped in $$0.45\ \mathrm{cm} by a $$nail. What is the average force exerted by the nail on the hammer?

$$1.6 \times 10^3$\ \mathrm{N}$$

Question 1

A car moves at a constant speed of 15 mph around a circular track. Which of the following statements is true about its acceleration?

Accepted Answer

The car has nonzero acceleration because its velocity direction is changing.

Question 2

A stone is thrown into the air at an angle above the horizontal with negligible air resistance. Which graph best represents the stone's speed $$v as a $$function of time $$t$$ while it is in the air?

Accepted Answer

A V-shaped graph, decreasing then increasing.

Question 3

Bob on the shore sees Alice on the water in a boat. Bob notes that relative to him, Alice is moving $$+15\ \mathrm{m/s}$$ and the boat has a speed $$+10\ \mathrm{m/s}. $$What is Alice’s velocity as seen by her dog Chloe sitting on the boat?

Accepted Answer

$$+5\ \mathrm{m/s}$$

Question 4

A hockey puck of mass $$0.160\ \mathrm{kg} is at $$rest on a frictionless surface. At $$t=0$$, a player applies a force of $$0.250\ \mathrm{N}$$ parallel to the $$x-$$axis for $$2.00\ \mathrm{s}. $$What is the speed of the puck at $$t=2.00\ \mathrm{s}$$?

Accepted Answer

$$1.56\ \mathrm{m/s}$$

Question 5

A bartender slides a $$0.500\ \mathrm{kg}$$ glass of liquid along a smooth countertop with an initial speed of $$2.00\ \mathrm{m/s}. If $$the frictional force is $$0.500\ \mathrm{N}$$, how far does the glass travel before stopping?

Accepted Answer

$$4.00\ \mathrm{m}$$

Question 6

On Pluto, the acceleration due to gravity is $$0.54\ \mathrm{m/s^2$}. If an $$astronaut weighs $$260\ \mathrm{N} on $$Earth, what is their weight on Pluto?

Accepted Answer

$$61\ \mathrm{N}$$

Question 7

A man is dragging a trunk up a loading ramp inclined at $$30^\circ. $$What is the magnitude of the force $$|F|$$ necessary for the component of $$F$$ parallel to the ramp to be $$60\ \mathrm{N}$$?

Accepted Answer

$$60/\cos 30^\circ$$

Question 8

Puck 4 has twice the mass of puck 5. Both are at rest at $$t=0$$ when a force $$F is $$applied to both. If puck 4 goes a distance $$x_4 in a $$given time, how far does puck 5 go in the same time?

Accepted Answer

$$x_5 = 2x_4$

Question 9

A $$72.6\ \mathrm{kg}$$ person stands on a scale in an elevator. If the scale reads $$800\ \mathrm{N}$$, what is the magnitude and direction of the elevator's acceleration?

Accepted Answer

$$1.1\ \mathrm{m/s^2$}$$, upward

Question 10

A $$1.43\ \mathrm{kg}$$ hammer head moving at $$3.2\ \mathrm{m/s} is $$stopped in $$0.45\ \mathrm{cm} by a $$nail. What is the average force exerted by the nail on the hammer?

Accepted Answer

$$1.6 	imes 10^3$\ \mathrm{N}$$

Question 11

Which of the following statements about Newton's Third Law is correct?

Accepted Answer

Action and reaction forces are equal in magnitude and opposite in direction.

Question 12

A world-class sprinter starts out of the starting blocks with an acceleration of $$25\ \mathrm{m/s^2$}. If $$the sprinter's mass is $$55\ \mathrm{kg}$$, what is the magnitude of the force the sprinter must exert on the blocks?

Accepted Answer

$$1,375\ \mathrm{N}$$

Question 13

Which body exerts the force that propels a sprinter out of the starting blocks?

Accepted Answer

The starting blocks

Question 14

A block of mass $$m$$ sits at rest on a horizontal surface. Which of the following is true about the forces acting on the block?

Accepted Answer

The normal force equals the weight in magnitude but is not an action-reaction pair.

Question 15

A $$0.5\ \mathrm{kg}$$ object is acted on by a net force of $$2.0\ \mathrm{N}$$ for $$3.0\ \mathrm{s}. $$What is its final velocity if it started from rest?

Accepted Answer

$$12\ \mathrm{m/s}$$

Question 16

A $$10\ \mathrm{kg}$$ box is pulled across a horizontal floor by a rope with a force of $$50\ \mathrm{N} at an $$angle of $$30^\circ$$ above the horizontal. If the coefficient of kinetic friction is $$0.2$$, what is the acceleration of the box?

Accepted Answer

$$2.6\ \mathrm{m/s^2$}$$

Question 17

Which of the following is NOT a fundamental force in nature?

Accepted Answer

Frictional force

Question 18

A $$2.0\ \mathrm{kg}$$ block is suspended by two ropes as shown. If the block is at rest, what is the tension in each rope?

Accepted Answer

Depends on the angles of the ropes

Question 19

A $$5.0\ \mathrm{kg}$$ object is moving with a velocity of $$2.0\ \mathrm{m/s} to $$the right. A net force of $$10\ \mathrm{N}$$ acts to the left for $$1.0\ \mathrm{s}. $$What is the final velocity?

Accepted Answer

$$0\ \mathrm{m/s}$$

Chapter 04

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드