Physics Fall Final Exam Study Guide

A 25 kg chair initially at rest on a flat surface requires a 165 N horizontal force to set in motion. Once the chair is in motion, a 127 N horizontal force keeps it moving at a constant velocity. a) Find the coefficient of static friction between the chair and the floor b) Find the coefficient of kinetic friction between the chair and the floor

-.67 -.6

What average net force is required to bring a 1500-kg car to rest from a speed of within a distance of 55 m?

-1.1 * 10^4 N

A football is kicked at an angle of 37º at an initial velocity of 20.0 m/s. -Determine the components of velocity -Determine the time of flight -Calculate the maximum height it will reach -How far it will hit the ground

-16 m/s and 12 m/s -2.44 secs -7.35 m -39.04 m

A stone is thrown w/ velocity = 20 m/s at 30º above horizontal from the top of a 40 m tall building and lands on the ground below. -Find the components of initial velocity -Determine the time to reach the highest point -Determine the maximum height reached -Determine the total time -Determine the horizontal range

-17 m/s and 10 m/s -1.02 secs -5.1 m -4.9 secs -84.77 m

An ice skater moving at 10.0 m/s coasts to a halt in 1.0 x 10^2 m on a smooth ice surface. What is the coefficient of friction between the ice and the skates?

.051

A 75 kg box slides down a 25.0º ramp with an acceleration of 3.60 m/s2. Find Uk between box and the ramp.

.061

A horizontal force of 200 N is applied to move a 55 kg television set across a 10 m level surface. What is the work done by the force of gravity on the television set?

0 J

An unstretched spring has a length of 20 cm and a spring constant of 100 N/m. If the spring is stretched to a new length of 27 cm, how much energy is stored in the spring?

0.25 J

A 10 kg box is sliding down a 30º incline. If the box is sliding at constant velocity, what is the coefficient of kinetic friction?

0.58

If the forces exerted on a 2-kg object are 50 N east and 30 N west, what is object's acceleration?

10 m/sec2

A 2.0 kg otter starts from rest at the top of a muddy plank 85 cm long and slides down to the bottom in .50 s. What net force acts on the otter along the incline?

13.6 N

Using a metric ruler with 1 mm divisions, you find the sides of a rectangular piece of plywood are 3.54 cm and 4.85 cm. You calculate that the area is 17.1690 cm2. To the correct number of significant figures, the result should be expressed as

17.2 cm2

An archaeologist climbs the Great Pyramid in Giza, Egypt. The pyramid's height is 136 m and its width is 2.30 x 10^2 m. What is the magnitude and the direction of the displacement of the archaeologist after she has climbed from the bottom of the pyramid to the top?

178 m

A 20 N box is pulled up a 20 m ramp that has a 40º incline by a force of 115N that points along the ramp. If the coefficient of kinetic friction is 0.22, calculate the change in the box kinetic energy.

1974 J

A student with a mass of 66.0 kg climbs a staircase in 44.0 s. If the distance between the base and the top of the staircase is 14.0 m, how much power will the student deliver by climbing the stairs?

206 W

A 2.0 x 10^3 kg car accelerates from rest under two forces. One is a forward force of 1140 N provided by traction between the wheels and the road. The other is a 950 N resistive force. How far must the car travel for its speed to reach 2.0 m/s?

21 m

A car accelerates uniformly from rest to a speed of 6.6 m/s in 6.5 s. Find the distance the car travels during this time.

21 m

What is the average power output of a weightlifter who can lift 250 kg 2.0 m in 2.0 seconds?

2500 watts

If Joe rides his bicycle in a straight line for 15 minutes with an average velocity of 12.5 km/h south, how far has he ridden?

3.10 km

How many seconds are there in a solar year (365.24days)?

3.1557 X ten to the power of 7 sec

A "DO NOT ENTER" sign hangs from 2 cables. Both the cables are at an angle of 45 degrees. The tension in each cable is 25 N. What is the mass of the sign?

3.6 kg

A 27 kg box is dragged 4.0 meters across the floor by a rope that is angled at 25º above horizontal. The tension in the rope is 85 N and the coefficient of friction between the box and the floor is 0.20. How much work is done by the tension force?

310J

The density of aluminum is 2.70 g/cm3. The volume of a solid piece of aluminum is 1.50 cm3. Find its mass.

4.05 g

A bus slows down with an average acceleration of -1.8 m/sec2. How long does it take the bus to slow from 9.0 m/s to a complete stop?

5.0 seconds

An 80 kg hiker walks a distance of 4000 m up a mountain at an average angle of 10 degrees above horizontal. What is the change in the hiker's potential energy? Calculate the height first.

5.45 x 105 J

A mule uses a rope to pull a box that weighs 3.0 x 10^2 N across a level surface with constant velocity. The rope makes an angle of 30.0º above the horizontal, and the tension in the rope is 1.0 x 10^2 N. What is the normal force of the floor on the box?

50.0 N

A ball with a mass of .3 kg is thrown upward from ground level with an initial velocity of 23 m/s. How much total mechanical energy does it have at maximum height?

79 J

Calculate the mass of a gold sphere with a radius of 10.0cm and density of 19.3g/cm3

8.08 X ten to the power of four g

During a race on level ground, Amanda runs with an average velocity of 6.02 m/sec to east. What is her displacement after 137 seconds?

825 m

A wooden block with a mass of 10kg is sliding down a 30 degree incline. Calculate the normal force on the block.

85 N

A 51 kg crate slides 5 m down a frictionless ramp that is inclined at 20 degrees with the horizontal. How much work is done by gravity?

855 J

Find the acceleration of an amusement park ride that falls from rest to speed of 28 m/s in 3.0 s.

9.3 m/sec2

A sign with a mass of 50 kg is suspended in equilibrium by two cables. Cable 1v applies a horizontal force to the right of the object and has a tension, FT1. Cable 2 applies a force upward and to the left at an angle of 30.0º above horizontal and has a tension, FT2. What is FT2?

980 N

A student attaches a rope to a 20.0 kg box of books. He pulls with a force of 90.0 N at an angle of 30.0º above the horizontal. The coefficient of kinetic friction between the box and the sidewalk is 0.500. A) Find the X component of the force vector B) Find the Y component of the force vector C) Find the Fg D) Find the Fn E) Find the acceleration of the box

A) 78 N B) 45 N C) 196 N D) 151 N E) .125 m/s^2

Which of the following forces is an example of a contact force?

Frictional force

A hammer drives a nail into a piece of wood. Identify an action-reaction pair, and compare the forces exerted by each object.

The hammer exerts a force on the nail; the nail exerts a force on the hammer.

A tennis ball is dropped from the top of a tall building. A second tennis ball is thrown from the same building. Make a statement about the acceleration of each tennis ball.

They both fall with the same acceleration because they are in free fall

Which would hit the ground first if dropped from the same height in a vacuum—a feather or a metal bolt?

They will hit the ground at the same time

Weak spring have smaller spring constant.

True

A 10 Kg crate that starts with a velocity of 1.5 m/s is pulled a distance of 5 m up a 20 degree incline by a 100 N force. The coefficient of friction is 0.4. Determine: a) X & Y component of gravity b) The work done by gravity c) The work done by friction

a) 34 N and 92.1 N b) 165 J c) 180 J

Frame of reference

any spot your doing your measurement from as long as it is not accelerating

Which of the following is a scalar quantity? a. displacement b. velocity c. force d. speed

d. speed

Ball A is thrown twice as fast as ball B. If ball A has the same mass as ball B, then the kinetic energy of ball A is

four times as much as ball B

Moving objects tend to continue moving in the same direction at the same velocity. This is due to:

inertia

The Earth exerts a gravitational force of 100 N on a certain satellite that is in orbit. The force that this satellite exerts on the Earth

is equal to 100 N

A force does work on an object if a component of the force

is parallel to the displacement of the object

___________________ is the force that opposes the movement of two surfaces that are in contact and are sliding over each other.

kinetic friction

In a diagram, the length of a vector arrow represents the

magnitude of the vector

A measure of the inertia of an object is

mass

When is mechanical energy conserved? When is it not?

mechanical energy is conserved in the absence of frictional forces

If the net force on a car is zero, then the car could be

moving at constant velocity

When does a force do negative work? When does a force not do any work at all?

negative work when force and distance are in opposite directions; no work when force and distance are perpendicular or when distance = 0

The normal force acts on a surface in a direction _________________________ to the surface.

perpendicular

When a car's velocity is positive and its acceleration is negative, what is happening to the car's motion?

slowing down in positive direction

A baseball rolls off a .70 m high desk and strikes the floor .25 m away from the base of the desk. Find the time. How fast was the ball kicked?

t=.37 secs Vi=.66 m/s

Relative motion

the calculation of the motion of an object with regard to some other moving or stationary object

The magnitude of the force of gravity acting on an object is

weight

A car goes forward along at constant velocity. The additional force needed to bring the car into equilibrium is

zero; equilibrium is the state in which the net force on an object is zero