Department of Natural Sciences

DEPARTMENT OF NATURAL SCIENCES

COPPIN STATE COLLEGE

PHSC 101.101 Fall, 2000 Examination #2 Take Home Dr. Amah)

Name______Date ______

1.  Your car, which has a mass of 750 kilograms when you are driving, accelerates steadily from 0.00 to 100 kilometer/hour in 8.0 seconds. How much force must be applied during this acceleration? (Hint: Find a in units of m/s2) Show the calculation.

2.  A cantaloupe has a mass of 0.5 kilograms. Calculate the weight of this cantaloupe in Newton and in lbs. Show your work in the space provided.

3.  A typical CD systems uses 250 W of electric power per hour. If you play your CD for three hours in an evening, how much energy did you use? If energy costs $0.08/KWH, how much do you owe the electric company? (Hint: P = W/t or E/t; also, 1.0 kWh = kilowatt-hour = 1000 w)

4.  Calculate the kinetic energy of a 4.0 kg bowling ball traveling down the bowling lane at 10m/s. Calculate this kinetic energy in calories and Kilocaries.

5.  You are pushing a wagon, which is initially at rest, with a constant force of 10N. The mass of the wagon is 15 kg. What is the acceleration of the wagon?.

6.  According to Einstein’s famous equation, E = mc2 , how much energy is contained in a 1.0 lb grapes sitting on your desk? (Hint: You need to convert pounds to kilograms . c = speed of light = 3.0 x 108 m/s).

7.  Calculate the momentum of:

a.  A 200 gram riffle bullet traveling at 300 m/s

b.  A 70 kg person running at 10 m/s.

8.  A force of 50 N is required to push a student’s stalled motorcycle 10 m along a flat road in 20 seconds. Calculate the power in watts.

9.  A 1200-kg car whose speed is 6 m/s rounds a turn whose radius is 30 m. Calculate the centripetal force on this car.

10. A woman standing before a cliff claps her hands, and in 2.8 seconds later, she hears the echo. How far away is the cliff? The speed of sound in air at ordinary temperatures is 343 m/s

11. The acceleration of gravity on Jupiter is about 25 m/s2 and your mass is 70 kg. What is your weight on Jupiter? What would your mass have to be in order to weigh this amount on earth? (Hint: The acceleration of gravity on earth is 9.8m/s2)