Title: guiding and description
Course: Physics copy 1

Q: In the demonstration to the left, an apple and a grape are released at the same time. What can you conclude from the demonstration? | link
- that objects of different mass accelerate at the same rate near the earths surface. (That is correct. In our study of projectiles, its important to realize that our colculations are independent of mass.)
- That object of different mass experience the same force of gravity near the earth's surface. (Wrong. Mass and force of gravity are proportional.)
- That objects of different mass have identical force and thus identical accellerations near the earth's surface. (Worng. The force of gravity is proportional to mass.)
- That the force of gravity and mass are idependent of each other. (wrong. Acceleration due to gravity is independent of mass, force of gravity is proportional to mass.)
- That grapes have a much higher density than apples.
A: that objects of different mass accelerate at the same rate near the earths surface.

Description Blank 1

Description Blank 2

What do you think the initial vertical component of velocity ($$v_{oy}$$) is in each of the cases?

Q: In the demonstration below one billiard ball will be dropped and the other will be launched to the left. Which one do you think will reach the ground first?

link

In the demonstration above you see two billiard balls, what can you conclude about the motion of the billiard balls?
- That horizontal motion has no effect on vertical motion. (That's correct. Acceleration due to gravity is constant and downwards.)
- That the billard ball on the left has more mass than the billiard ball on the right. (The billiard balls in this demonstration heve identical masses.)
- That the billiard ball on the right has more mass than the billiard ball on the left. (The billiard balls in this demonstration heve identical masses.)
- That the kinetic energy of the billiard balls is nearly identical for any time t after their release (The kinetic energy of these balls is always different since the total velocity at any time t is different.)
A: That horizontal motion has no effect on vertical motion.

Q: link

A ball has been pushed off a table with a horizontal velocity of 1m/s. At a particular instant in time its vertical velocity is -1 m/s. The direction of the total velocity vector is _____ degrees directed down from the horizontal.

Enter all angles as positive degrees measured downwards from the horizontal.
A: -45 / 45

Q: A ball has been pushed off a table with a horizontal velocity of 1m/s. At a particular instant in time its vertical velocity is 1 m/s. The total velocity is_____ m/s.
A: 1.41 (± 0.1)

Q: A ball has been pushed off a table with a horizontal velocity of 1m/s. At a particular instant in time its vertical velocity is -2 m/s. The direction of the total velocity is_____ degrees directed down from the horizontal.
A: -63 (± 2) / 63 (± 2)
Feedback ("-63"): 63:2

Q: A ball has been pushed off a table with a horizontal velocity of 1m/s. At a particular instant in time its vertical velocity is -2 m/s. The total velocity is_____ m/s.
A: 2.24 (± 0.2)