Mastering Physics Assignment 1

Assignment 1: Kinematics in 2 and 3 Dimensions
Due: 2:00am on Saturday, September 4, 2010
Note: To understand how points are awarded, read your instructor's Grading Policy.
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Arrow Hits Apple
An arrow is shot at an angle of

above the horizontal. The arrow hits a tree a horizontal distance

away, at the same height above the ground as it was shot. Use

for the

magnitude of the acceleration due to gravity.
Part A
Find

, the time that the arrow spends in the air.

Hint A.1

Find the initial upward component of velocity in terms of D.
Hint not displayed

Hint A.2

Find the time of flight in terms of the initial vertical component of velocity.
Hint not displayed

Hint A.3

Put the algebra together to find

symbolically.

Hint not displayed
Answer numerically in seconds, to two significant figures.
ANSWER:

= 6.7
Correct

Suppose someone drops an apple from a vertical distance of 6.0 meters, directly above the point where the arrow hits the tree.
Part B
How long after the arrow was shot should the apple be dropped, in order for the arrow to pierce the apple as the arrow hits the tree?
Hint B.1

When should the apple be dropped
Hint not displayed

Hint B.2

Find the time it takes for the apple to fall 6.0 meters
Hint not displayed

Express your answer numerically in seconds, to two significant figures.
ANSWER:

= 5.6
Correct

=

Correct

Circular Launch
A ball is launched up a semicircular chute in such a way that at the top of the chute, just before it goes into free fall, the ball has a centripetal acceleration of magnitude 2 .

Part A
How far from the bottom of the chute does the ball land?
Hint A.1

Speed of ball upon leaving chute
Hint not displayed

Hint A.2

Time of free fall
Hint not displayed

Hint A.3

Finding the horizontal distance
Hint not displayed

Your answer for the distance the ball travels from the end of the chute should