Two identical balls are thrown simultaneously
from a bridge at 20 m/s. Ball A has an initial
trajectory angle of 30° above the horizontal; ball
B, 30° below the horizontal. Assuming no air
drag (and constant g), what will you see?
1.
2.
3.
4.
Both hit the water at the same time.
Both hit the water with the same impact speed.
Both reach the same maximum height.
Both move the same horizontal distance before
impact.
5. More than one of the above.
10/9/15
Oregon State University PH 211, Class #6
1
A battleship simultaneously fires two shells at enemy ships.
The shells follow the paths shown here. Assuming
negligible air drag, which ship gets hit first?
A.
B.
C.
D.
10/9/15
Ship A
Ship B
They are hit at the same time.
There is not enough information.
Oregon State University PH 211, Class #6
2
You’re on the surface of planet Irth, where they haven’t
yet invented calculators, but fortunately the
acceleration due to gravity is 10.0 m/s2. You kick a
stone horizontally off a cliff at an initial velocity of
40.0 m/s and it lands at an impact angle of –45.0° on
the level ground below the cliff. How high is the cliff?
10/9/15
1.
20.0 m
2.
40.0 m
3.
80.0 m
4.
120 m
5.
None of the above.
Oregon State University PH 211, Class #6
3
A hot air balloon rises at speed v. The balloonist hurls a
ball horizontally outward at v0 in his frame of reference.
Which path best represents the path of the ball in the
Earth’s frame?
10/9/15
Oregon State University PH 211, Class #6
4