1

. A sledge loaded with bricks has a total mass of 17

.5 kg and is pulled at constant speed by a

rope inclined at 20

.9° above the horizontal

. The sledge moves a distance of 19

.4 m on a

horizontal surface

. The coefficient of kinetic friction between the sledge and surface is 0

.500

.(a) What is the tension in the rope?

N

(b) How much work is done by the rope on the sledge?

kJ

(c) What is the mechanical energy lost due to friction?

kJ

2

. A mechanic pushes a 2

.80 103kg car from rest to a speed of v, doing 5,000 J of work in

the process

. During this time, the car moves 29

.0 m

. Neglecting friction between car and road,

find each of the following

.(a) the speed v

m/s

(b) the horizontal force exerted on the car

N

3

. Two blocks are connected by a light string that passes over two frictionless pulleys as in the

figure below

. The block of mass m2 is attached to a spring of force constant k and m1 > m2

. If

the system is released from rest, and the spring is initially not stretched or compressed, find

an expression for the maximum displacement d of m2

. (Use any variable or symbol stated

above along with the following as necessary: g

.)

d =

4

. A block of mass m = 6

.80 kg is released from rest from point

and slides on the

frictionless track shown in the figure below

. (Assume ha = 8

.00 m

.)

(a) Determine the block's speed at points

point

point

and

. m/s

m/s

(b) Determine the net work done by the gravitational force on the block as it moves from

point

to point

. J

5

. The system shown in the figure below is used to lift an object of mass m = 51

.5 kg

. A

constant downward force of magnitude F is applied to the loose end of the rope such that the

hanging object moves upward at constant speed

. Neglecting the masses of the rope and

pulleys, find the following

.(a) Find the required value of F

. N

(b) Find the tensions T1, T2, and T3

. (T3 indicates the tension in the rope which attaches the

pulley to the ceiling

.)

T1 =

T2 =

T3 =

N

N

N

(c) Find the work done by the applied force in raising the object a distance of 2

.20 m

. J

6

. A skier of mass 78 kg is pulled up a slope by a motordriven cable

.(a) How much work is required to pull him 50 m up a 30° slope (assumed frictionless) at a

constant speed of 2

.8 m/s?

J

(b) What power (expressed in hp) must a motor have to perform this task?

hp

7

. A pitcher claims he can throw a 0

.160kg baseball with as much momentum as a 2

.20g

bullet moving with a speed of 1

.50 103 m/s

.(a) What must the baseball's speed be if the pitcher's claim is valid?

m/s

(b) Which has greater kinetic energy, the ball or the bullet?

A

. The ball has greater kinetic energy

.B

. The bullet has greater kinetic energy

. C

. Both have the same kinetic energy

.8

. The force shown in the force vs

. time diagram in the figure below acts on a 3

.2kg object

.(a) Find the impulse of the force

. N ? s

(b) Find the final velocity of the object if it is initially at rest

. m/s

(c) Find the final velocity of the object if it is initially moving along the xaxis with a

velocity of

?1

.6 m/s

. m/s

9

. A 70

.0kg person throws a 0

.0470kg snowball forward with a ground speed of 27

.0 m/s

. A

second person, with a mass of 59

.0 kg, catches the snowball

. Both people are on skates

. The

first person is initially moving forward with a speed of 2

.50 m/s, and the second person is

initially at rest

. What are the velocities of the two people after the snowball is exchanged?

Disregard the friction between the skates and the ice

.thrower

catcher

m/s

m/s

10

. A railroad car of mass 2

.0 104 kg moving at 4

.00 m/s collides and couples with two

coupled railroad cars, each of the same mass as the single car and moving in the same

direction at 1

.20 m/s

.(a) What is the speed of the three coupled cars after the collision?

m/s

(b) How much kinetic energy is lost in the collision?

J

11

. A bullet of mass m = 8

.00 g is fired into a block of mass M = 240 g that is initially at rest at

the edge of a table of height h = 1

.00 m (see figure below)

. The bullet remains in the block,

and after the impact the block lands d = 2

.20 m from the bottom of the table

. Determine the

initial speed of the bullet

. ? m/s

12

. Consider a frictionless track as shown in the figure below

. A block of mass m1 = 4

.15 kg is

released from

. It makes a headon elastic collision at

with a block of

mass m2 = 11

.5 kg that is initially at rest

. Calculate the maximum height to which m1 rises after

the collision

. ? m