SI Physics 221
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Worksheet 1.7 Directional Forces, Tension
1. A rock (8.0 kg) falls from a window. What is the magnitude of force on the rock .8s
after its initial release?
What is the speed of the rock after having fallen 40 meters?
The rock falls into a garbage can that stops it after falling for .5m. Assume the garbage
slows its fall at a constant rate. What is the magnitude of deceleration?
What is the magnitude of force acted on the rock by the garbage?
2. 3 Forces F1 = 3N, F2=3 N, F3=8N, all act on a mass at the origin.
What is the magnitude of net force acting on the object?
3. A girl is standing on a scale in an elevator, her mass= 60kg.
What is her weight if the elevator is descending at a constant rate of 8m/s?
What is her weight if the elevator is descending with an acceleration of 3.0 m/s^2?
What is her weight if the elevator is ascending with an acceleration of 3.0 m/s^2?
What is her weight if the elevator is descending at a rate of 8m/s but is decreasing by 2 m
every second?
4. Three blocks of 1kg, 10kg, and 8kg, are each lined up left to right on a frictionless
surface. A leftward pointing force is applying 50N onto the block at the far right (8kg).
What is the magnitude of force exerted by the middle block on the right block?
What is the magnitude of force the left block exerts on the middle block?
If the order of the blocks is reversed, but the same force is applied what is the magnitude
of the force exerted by the left block on the middle block?
5. A mass is suspended as pictured below with theta being 60 degrees. What is the
tension on the left string?
6. A 1kg sphere hangs from the ceiling of a car. The car has a constant acceleration and
the string makes a 35 degree angle with the roof of the car, and does not move from that
position after being displaced.
What is the magnitude of horizontal acceleration of the car?