Question 1-3: A cannon fires a 2 kg cannonball horizontally off a 100-meters tall cliff with an initial velocity of 40 m/s in the x direction? Set the bottom of the cliff to be the zero potential, i.e. h = 0 at the bottom.
1. Calculate the Total Initial Energy (before) just after the cannon has been fired, when the cannonball has an initial velocity. Total Energy = PE (due to height) + KE (due to motion). Units should be in joules.
2. Calculate the Total Final Energy just before the cannon reaches the ground. Units should be in Joules.
3. Use Conservation of Energy to calculate the final velocity of the cannonball just before it reaches the ground. Units should be in m/s.
4. A 1 kg mass is dropped from rest from a height of 20 m above a flat horizontal table. What is the magnitude in the momentum of the mass lust before it hits the table? Units should be in kgm/s.
5. The kinetic energy of a ball is 600 J when its velocity is 3 m/s to the right. What is the kinetic energy of this mass when its velocity is 6 m/s to the left? Units should be in joules.
6. A 2 kg football is kicked with initial velocity of 50 m/s when it is at ground level. The football undergoes projectile motion and reaches the top of its path when it has a horizontal velocity of 25 m/s. How high does the football go above the ground assuming free fall conditions? (Hint: use Conservation of Energy. Total Energy = PE (due to height) + KE (due to motion)).
7. A 5kg block starts at rest at the top and slides down an inclined ramp that is 10 m high at the top. What is the velocity of the block when it is 5 m off the ground?
8. Relative to an initial height, an object raised twice as high has a gravitational potential energy that is
A) Half as much
B) Twice as much
C) Four times as much.
D) Need more information
9. A 2-kg ball is held 4 m above the ground. Relative to the ground its potential energy is
A) 6 J.
B) 8J.
C) 32J.
D) 80 J.
E) More than 80J.
10. Two identical golf carts move at different speeds. The faster cart has twice the speed and therefore has
A) Twice the kinetic energy.
B) Four times the kinetic energy.
C) Eight times the kinetic energy.
D) None a the above.