Name___________________________________
FREE FALL - P. 72
Physics Classwork 02/10/17
PH.07, 09, 10, 13
1) What is free fall? __________________________________________________________________________________
2) In the absence of air resistance, all objects fall at the same rate.
3) Which units are used to measure free fall?
4) Acceleration due to gravity is also called
A) negative velocity.
C) instantaneous velocity.
T or F
3)
4)
B) displacement.
D) free-fall acceleration.
5) What is the accepted value for the acceleration of objects in free fall?
5)
6) Which would fall with greater acceleration in a vacuum, a leaf or a stone?
A) the stone
B) the leaf
C) It is difficult to determine without more information.
D) They would accelerate at the same rate.
6)
7) A baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to
the mitt. From just after it leaves his hand until just before it returns, at what point in the ball's path
does it experience zero VELOCITY?
A) the instant it leaves the catcher's hand
B) never
C) the instant before it arrives in the catcher's mitt
D) at the top of its trajectory
7)
8) A baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to
the mitt. From just after it leaves his hand until just before it returns, at what point in the ball's path
does it experience zero ACCELERATION?
A) the instant before it arrives in the catcher's mitt
B) the instant it leaves the catcher's hand
C) at the top of its trajectory
D) never
8)
9) Which would hit the ground first if dropped from the same height in a vacuum, a feather or lead
weight?
A) the lead weight
B) They would be suspended in a vacuum.
C) They would hit the ground at the same time.
D) the feather
9)
10) When there is no air resistance, objects of different masses
A) fall with equal accelerations and similar displacements.
B) fall with different accelerations but similar displacements.
C) fall with equal accelerations but different displacements.
D) fall with different accelerations and different displacements.
10)
11) If we ignore air resistance, we expect objects that are falling toward Earth to move
A) slower then faster.
B) slower and slower.
C) at a constant velocity.
D) faster and faster.
AIR RESISTANCE - P. 100
12) Air resistance is what kind of contact force?
A) shear
B) compression
C) tension
11)
12)
D) friction
13) In what direction does the force of air resistance act? ____________________________________________
14) Why is air resistance considered a form of friction?
____________________________________________
___________________________________________________________________________________________
15) As the speed of an object moving through a fluid increases, the magnitude of the drag force decreases.
T or F
16) What happens to air resistance when an object accelerates? _______________________________________
___________________________________________________________________________________________
17) When an object falls through a liquid or gas, it will reach a speed where the force of gravity is
exactly balanced by the resistance of the liquid or gas. This speed is called ____.
A) acceleration
B) terminal velocity
C) viscosity
D) momentum
17)
18) When a person is skydiving, what happens to his/her velocity and acceleration if the air resistance becomes
equal to the force of gravity?
Acceleration: ___________________________________________________________________________
Velocity: _______________________________________________________________________________
FORCES IN 2 DIMENSIONS - P. 120
19) If you have to add two vectors that are at right angles to each other, how do you calculate the magnitude of the
resultant vector?
______________________________________________________________________________
20) A student adds two vectors with magnitudes of 2x102 and 4x101 . Taking into account significant
figures, which is the only possible choice for the magnitude of the resultant?
A) 160
B) 300
C) 200
D) 240
20)
21) A wolf spider runs 75 cm west, then turns and runs 50 cm south. Which choice gives the correct
solution for the resultant?
A) R2 = 752 502
B) R2 = 752 + 502 - 2(75)(50) cos 60
21)
C) R2 = 752 + 502
D) R2 = 752
502 - 2(75)(50) cos 90
22) A canoe heads west at 9.00 km/h in a river that flows north at 4.00 km/h. What is the
canoe's velocity relative to the earth?
22)