Physics Unit 5 Review 2012
Name ________________________________
Fill the following table with the correct symbols and units
Quantity
Symbol as used in
formulas
SI Unit
Gravitational Force
Mass
Distance
Tangential velocity
Centripetal acceleration
Centripetal force
Radius
1) What is the value for the universal gravitational constant G (include units)?_____________________
2) What is the mass of earth (include units)? __________________________________
3) What is the radius of the earth (include units)? ____________________________________
4) Suppose your 60 kg archenemy is standing on the surface of Jupiter. There is a gravitation force of 1,561 N
between your archenemy and Jupiter. The radius of Jupiter is 6.98 x 10 7 m. What is the mass of Jupiter?
Diagram: (Given + Unknowns)
Equation:
Substitute:
Solve:
5)
Suppose your 60 kg nemesis is standing on the surface of Pluto. There is a gravitational force of 36.3 N
between your nemesis and Pluto, which has a mass of 1.2 x 10 22 kg. What is the radius of the planet Pluto?
Diagram: (Given + Unknowns)
Equation:
Substitute:
Solve:
6)
Which of the following situations that will result in the least gravitational force between two objects?
A)
C)
7)
Large combined masses and small distance apart
Small combined masses and large distance apart
B) Large combined masses and large distance apart
D) Small combined masses and small distance apart
Suppose you are standing on earth. Explain how weight and gravitational force between you and earth are the
same thing.
8) Explain the difference between linear (tangential speed) and rotational (angular speed)
9) If the distance from the center of a merry-go-round to the edge is 1.2 m, what is the tangential (or linear) speed of
a 25 kg puggle that sits on the edge of merry-go-round with a centripetal force of 48 N? (DRAW A PICTURE AND USE
GUESS METHOD TO SOLVE)
Diagram: (Given + Unknowns)
Equation:
Substitute:
Solve:
10) Calculate the magnitude of the centripetal force experienced by the toy airplane, as viewed from the diagram
above. Record and bubble in your answer to the nearest tenth.
11) Centripetal force is
A) directed towards the center
C) both A and B
B) directed away from the center
D) neither A nor B
12) If the radius the doubled, what happens to the centripetal acceleration?
A) It doubles.
B) It quadruples.
C) It is reduced to ½
D) It stays constant.
13) If the tangential velocity is doubled what happens to the centripetal acceleration?
A) It doubles.
B) It quadruples.
C) It is reduced to ½
D) It stays constant.
14) If the centripetal acceleration doubles, what happens to the centripetal force?
A)
It doubles.
B) It quadruples.
C) It is reduced to ½
D) It stays constant.
15) Bruce Jenner, is the 1976 Montreal Olympic gold medalist in the decathlon. One competition of the
decathlon is the hammer throw, an athletic throwing event where the goal is to throw a heavy metal ball
attached to a wire and handle. Competitors gain maximum distance by swinging the hammer above their head
to set up the horizontal circular motion. Which of the following statements best describes the force and
acceleration of the hammer throw?
I)
II)
III)
IV)
A)
The acceleration is directed towards the center of the circle.
The acceleration is directed away from the center of the circle.
The force is directed towards the center of the circle.
The force is directed away from the center of the circle.
I and IV
B) I and III
C) II and III
D) II and IV
16) A ball is traveling in a circular path at a constant speed, the velocity is directed
A) along the path of the circle
C) towards the center of the circle
B) in a tangent of the circle
D) away from the circle.
17) For a planet moving in a circular path, in what direction is the force that holds the object in its trajectory?
A)
B)
C)
D)
In the direction of the tangential motion
Radially outward from the center of rotation
Radially inward towards the center of rotation
Perpendicular to the plane of rotation
18) What relationship exist between the tangential velocity and centripetal acceleration?
A)
B)
C)
D)
They
They
They
They
are
are
are
are
parallel to each other going in the same direction.
parallel to each other going in opposite directions.
perpendicular to each other with the acceleration directed towards the center.
perpendicular to each other with the velocity directed towards the center.
19) Two spheres (m1 and m2) are separated a distance d, apart. The gravitational force between the two
spheres is Fg. If the spheres are separated to a distance of 3d, what is the new gravitational force between the
spheres?
m1
m2
d
A)
3(Fg)
B) 9(Fg)
C) Fg / 3
D) Fg / 9
20) A 45 kg puggle and a 130 kg puma are at a standoff (staring at each other) with a distance 70 m between them.
What is the magnitude of the force of gravity between the puggle and the puma?
Diagram: (Given + Unknowns)
Equation:
Substitute:
Solve:
21) A 0.40 kg ball on a 0.50 m string rotates in a circular path in a vertical plane. If the tangential speed of the ball at
the bottom of the circle is 4.0 m/s, what is the centripetal force that maintains circular motion? (DRAW A PICTURE
AND USE GUESS METHOD TO SOLVE)
A) 5.6 N
C) 11 N
Diagram: (Given + Unknowns)
B) 13 N
D) 20.0 N
Equation:
Substitute:
Solve:
22) An airplane is flying in a horizontal circle at a speed of 105 m/s. The pilot’s mass is 80.0 kg. (g = 9.81 m/s2) If
the pilot does not want the centripetal acceleration to exceed 5,000 m/s 2, what is the minimum radius of the plane’s
path? What is the centripetal force on the pilot at this radius? (DRAW A PICTURE AND USE GUESS METHOD TO SOLVE)
Diagram: (Given + Unknowns)
Equation:
Substitute:
Solve: