1. An arrow is shot horizontally with a speed of 20. m/s from the top of a tower 60. m high. The time to reach the ground will be
a) 8.9 s.
b) 7.1s.
c) 3.5 s.
d) 2.6 s.
e) 1.0 s.
2. A projectile is launched from the top of a building with an initial velocity of 30.0 m/s at an angle of 60.0° above the horizontal. The magnitude of its velocity at t = 5.00 s after the launch is
a) -23.0 m/s.
b) 7.3 m/s.
c) 15.0 m/s.
d) 27.5 m/s.
e) 50.4 m/s.
3. A ball is thrown at an angle between 0° and 90° with respect to the horizontal. Its velocity and acceleration vectors are parallel to each other at a launch angle of
a) 0°.
b) 45°.
c) 60°.
d) 90°.
e) none of the above.
4. During practice two baseball outfielders throw a ball to the shortstop. In both cases the distance is 40.0 m. Outfielder 1 throws the ball with an initial speed of 20.0 m/s, outfielder 2 throws the ball with an initial speed of 30.0 m/s. In both cases the balls are thrown and caught at the same height above ground.
a) Ball 1 is in the air for a shorter time than ball 2.
b) Ball 2 is in the air for a shorter time than ball 1.
c) Both balls are in the air for the same duration.
d) The answer cannot be decided from the information given.