Download Unit 7 Homework

1401 Homework
Projectile Motion
1. An object is launched at 80 degrees above horizontal with speed 6m/s. Calculate the
horizontal and vertical launch velocities.
2. An object is launched at 45 degrees above horizontal with speed 6m/s. Calculate the
horizontal and vertical launch velocities.
3. An object is launched at 20 degrees above horizontal with speed 6m/s. Calculate the
horizontal and vertical launch velocities.
4. An object is launched at 30 degrees below horizontal with speed 6m/s. Calculate the
horizontal and vertical launch velocities.
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5. A solid steel ball rolls in a straight line along a level surface with constant speed. The ball
then rolls off the level surface moving through the air with negligible air-resistance,
subsequently striking the ground which is some distance below the level surface.
Draw a motion diagram for the ball while on the level surface.
Use the definition of acceleration to determine the acceleration of the ball when it is on the
level surface and behaving as described above.
Use Newton’s Second Law and your previous answer to determine the size of the net force
acting on the ball on the level surface.
Sketch the trajectory of the ball all the way to the floor.
When is the ball going fastest? Slowest?
Does the speed of the ball change continuously
while in flight? Explain.
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Use the definition of acceleration to determine the direction of the average acceleration for
the two vector velocities you chose.
Use Newton’s Second Law and your previous answer to determine the direction of the net
force acting on the ball while in flight.
6. Given the following data: The solid steel ball rolls in a straight line along the level surface
with a constant speed of 6.0m/s. The level surface is 3.0m above ground level.
What is the ball’s launch speed? Launch angle?
While the ball is in flight, what is its acceleration?
Calculate the time the ball is in flight.
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Calculate the vertical component of the ball’s velocity at the instant before the ball strikes the
floor.
What is the horizontal component of the ball’s velocity at the instant before the ball strikes the
floor.
Calculate the velocity’s angle below horizontal the instant before it strikes the floor.
Use the Pythagorean theorem to calculate the speed of the ball at the instant before it strikes
the floor.
Calculate the “range” of the flight, i.e. the horizontal displacement from launch to first-strike
with the floor.
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