Physics

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Week One Physics Assignment

 

NAME_____________________________________

This homework covers material found in the Prologue, Chapter 1, and Chapter 2 of your textbook.

Instructions:  Please answer each of the following questions. Please be sure that you show full solutions to arithmetic problems (just showing answers will result in no credit). Short answer questions should be answered in complete sentences. Watch your positive/negative signs. You must show the correct units of your answer!

 

  1. . Suppose a stretch of land in the savanna is 124 m long. If a cheetah reaches its top speed (starting at rest) within that entire stretch, what is its final speed? Assume acceleration is constant at 4 m/s2 and the cheetah is running in a straight line (towards some unsuspecting prey?). (10 points)

 

 

 

  1. You launch a cannonball at an angle of 35° and an initial velocity of 36 m/s (assume yi = yf = 0 meters). Calculate the time the cannonball spent in the air. Assume no air resistance and that the cannonball is launched on Earth (g = -9.81 m/s2). (10 points)

 

 

 

  1. Using your answer from #2, how far did the cannonball travel? (10 points)

 

 

  1. A 102 kg box is pushed on a linoleum floor with an acceleration of 2.5 m/s2. The force of kinetic (moving) friction between the box and the floor is 42 N. What is the net force acting on the box? (10 points)

 

 

 

 

  1. What is the force acting on a 1200 kg car that is driving around a circle of radius 35 m at a constant linear velocity of 9 m/s? (10 points)

 

 

 

  1. If two 1000 kg trucks are sitting 20 meters apart, what happens to the gravitational force if the trucks are moved to 40 meters apart? What if, instead of moving the trucks, one of the trucks was 2000 kg instead? How would that affect the gravitational force? (10 points)

 

 

 

 

  1. What is the average speed of a housecat that runs 20 m in 4.5 seconds? (10 points)

 

 

 

 

  1. Which has greater inertia: the Sun or the Earth? Which exerts a greater gravitational force: the Earth on the Sun or the Sun on the Earth? (10 points)

 

 

 

  1. What happens to the period of a pendulum if the frequency is halved? (10 points)

 

 

 

 

  1. How long would it take a car to reach 50 mph (22.35 m/s) from rest if it accelerates at a rate of 2.8 m/s2? (10 points)