During a violent thunderstorm, hail of diameter 1.0 cm falls directly downward at speed of 25m/s. There are estimated to be 120 hailstones per cubic meter of air. (a) What is the mass of each hailstone (density = 0.92 g/cm^3)? (b) Assuming that the hail does not bounce, find the magnitude of the average force on a flat roof measuring 10m x 20m due to the impact of the hail.© BrainMass Inc. brainmass.com October 16, 2018, 9:27 pm ad1c9bdddf
Hint: during impact the force on a hailstone from the roof is approximately equal to the net force on the hailstone because the gravitational force on it is small.
Mass/ Volume = Density
The solution finds the magnitude of the average force.
Impulse, momentum conservation, potential energy
1. Define the term impulse.
2. Using the principle of momentum conservation, explain what happens when a moving billiard ball collides with a stationary ball (cue ball hitting the eight ball).
3. Explain the difference between energy and power and how they are related to work. Give examples of each).
4. A 1000 kilogram care is lifted 1 meter.
a. What is the potential energy with respect to the floor?
b. If the car is lifted 2 meters high, what is the new value of potential energy with respect to the floor?
c. Explain the following: Potential energy of an object varies linearly with position (height).
5. As you catch a fast-moving fastball, why is it wise to move your hand in the direction of the ball's motion? Explain in terms of work and energy.
6. If a sprinter running at a speed of 10 meters per second could convert his/her kinetic energy into upward motion, how high could he/she jump?
7. What various forms of energy are present as you shoot a bow and arrow?
8. a. If you push a lawn mower across a yard in 10 seconds, how does the work done compare with pushing it across the same yard in 20 seconds? Explain why.
b. How does the power for 10 seconds compare to the power for 20 seconds?
9. How many kilometers per liter will a car obtain if its engine is 25 percent efficient and it encounters and average force of 1000 Newtons? Assume the energy content of gasoline is 40,000,000 joules per liter (J/L).View Full Posting Details