Fall Semester Review: Physics Situation 1: Air resistance is ignored. A person is standing on a bridge that is 150 m above a river. a. If a stone with a mass of 25 g was released from the top of the bridge, what is the velocity of the stone just before it hits the water?

b. How fast is the stone traveling after the stone has fallen 75 m? c. A fish in the river is going to throw a stone of unknown mass back to the person on the bridge. At what velocity would the fish have to thrown the stone to just reach the top of the bridge?

Situation 2: A soccer ball is kicked at an angle of 32 o above the horizon at an initial velocity of 4.5 m/s. The mass of the soccer ball is 0.33 kg. a. What are the horizontal and vertical components of the soccer ball when it is first kicked?

b. What is the initial kinetic energy of the soccer ball? c. Negating resistance, what is the maximum height of the soccer ball?

d. What is the total distance the soccer ball will travel? e. What is the momentum of the soccer ball at the maximum height?

Situation 3: A worker drags a 20 kg box across the floor with a force of 75 N pulling horizontally. a. What is the perpendicular force acting on the box?

b. If the box is pulled at a constant 0.55 m/s horizontally across the floor, how much time will pass to move the box 56 m? c. If the box is moved at a constant velocity of 0.55 m/s, what is the frictional force?

d. At the constant velocity of 0.55 m/s, what is the coefficient of sliding friction? e. If the coefficient of sliding friction was 0.155, with what acceleration will the box move?

f. What is the momentum of the box with the constant velocity? g. If the rope was pulled at an angle of 32 o, How would the perpendicular force change? h. With the box being pulled at the angle as above, what would happen to the coefficient of sliding friction?

Situation 4: A teacher lifts a stack of books that have a total mass of 5.6 kg from the floor to a shelf 3.2 m above the ground. a. What is the work done by the teacher on the books? b. What is the change in the gravitational potential of the books?

c. As the books are being placed, one of the books with a mass of.099 kg slides off the top and falls to the floor, hitting the teacher on his big toe. What is the final velocity of the book as it hits the big toe?

d. How much momentum does the book in c above have just before the toe is hit? e. How much force is transferred to the teachers’ big toe in the situation in c above? It takes a 0.03 s impact on the toe.

Situation 5: A 43 kg child at a water park starts at rest at the top of a water slide. It will take the child 5.6 s to rest the bottom of a 75 m slide. Assume zero friction. a. What is the average speed of the child when the child slides down?

b. What is the final velocity of the child just before stopping at the bottom? c. How high is the starting platform for the slide?

d. To stop, friction is introduced. If the speed of the child at the bottom is 6.5 m/s while the friction is applied, how much mechanical energy is loss in order to stop?

e. While sliding down the water slide in a tube, a 43 kg child runs into a 32 kg child that was standing at rest in the middle of the slide. If the velocity of the 43 kg child at the time of the collision was 4.5 m/s, what is the velocity now that the two children are in the same tube? Negate the mass of the tube.

f. What is the impulse that the 32 kg child imparted onto the 43 kg child in e above?

Situation 6: A 0.25 kg marble is to roll horizontally along the top of a table for a distance of 45 cm in 0.25 s. At the end of the 45 cm, the marble rolls off the top that is 0.95 cm above the floor. a. What is the velocity of the marble just before the marble rolls off the table top?

b. How much time will pass before the marble hits the floor? c. Where along the floor will the marble hit as measured from the base of the table?

d. A marble of the same mass is set at the edge of the table top. The initial marble in motion is m 1 and the marble at rest is m 2. If m 1 rolls toward m 2 in the original situation above, m 1 hits m 2 knocking m 2 off the table top. Mathematically prove that the horizontal displacement of m 2 would be the same as the horizontal displacement of m 1 as found in c above.