# Applying Newton’s Laws

Applying Newton’s Laws.

I need an explanation for this Physics question to help me study.

1-

A 9.00-

kg



k

g

block of ice, released from rest at the top of a 1.09-

m



m

-long frictionless ramp, slides downhill, reaching a speed of 2.94

m/s



m

/

s

at the bottom.

#### Part A

What is the angle between the ramp and the horizontal?

#### Part B

What would be the speed of the ice at the bottom if the motion were opposed by a constant friction force of 10.1

N



N

parallel to the surface of the ramp?

v

=

nothing

m/s

2-

A stockroom worker pushes a box with mass

12.0

kg



k

g

on a horizontal surface with a constant speed of

3.30

m/s



m

/

s

. The coefIficient of kinetic friction between the box and the surface is

0.25.

#### Part A

What horizontal force must the worker apply to maintain the motion?

F

=

3-

A 50.0

kg



k

g

ice skater spins about a vertical axis through her body with her arms horizontally outstretched, making 2.00 turns each second. The distance from one hand to the other is 1.5

m



m

. Biometric measurements indicate that each hand typically makes up about 1.25

%

of body weight.

#### Part A

What horizontal force must her wrist exert on her hand?

F

=

N



N

#### Part B

Express the force in part (a) as a multiple of the weight of her hand.

F

=

w



.

4-o-

A rocket of initial mass

135

kg



k

g

(including all the contents) has an engine that produces a constant vertical force (the thrust) of

1710

N



N

. Inside this rocket, a

12.5-

N



N

electrical power supply rests on the floor.

#### Part A

Part complete

Find the initial acceleration of the rocket.

 ainitial ${}_{}$ a i n i t i a l = 2.87 ms2  m s 2

Correct

#### Part B

When the rocket has reached an altitude of

120

m



m

, how hard does the floor push on the power supply? Neglect the air resistance.

N

=

5–o—

A 8.60-

kg



k

g

block of ice, released from rest at the top of a 1.37-

m



m

-long frictionless ramp, slides downhill, reaching a speed of 2.86

m/s



m

/

s

at the bottom.

#### Part A

What is the angle between the ramp and the horizontal?

ϕ

=

${}^{}$

#### Part B

What would be the speed of the ice at the bottom if the motion were opposed by a constant friction force of 10.6

N



N

parallel to the surface of the ramp?

v

=

nothing

m/s



m

/

s

Applying Newton’s Laws