1) A spring with spring constant 450 N/m is compressed 15cm and is used to fire a 5g plastic ball straight up in the air. Find: a) the launch speed

b) the maximum height to which the ball rises

2) A pendulum with a mass of 50g on it at a height of 30cm is allowed to swing. At the bottom of its swing it strikes a horizontal spring that compresses 5cm in stopping the pendulum. What is: a) the spring constant?

b) the speed of the pendulum bob when the spring is only compressed by 3cm?

3) A ball of coefficient of restitution 0.86 is dropped from a 20m high balcony. How many times does it pass a mark at a height of 8.62m?

4) Inspector Gadget loses control of his spring shoes and after leaping off a 15m high balcony, reaches a height of 1.7m after 4 bounces. What was the coefficient of restitution of his shoe springs?

5) A ball u =0.62 is dropped from a height of 65cm. If it has a diameter of 3.8cm, how many bounces will it appear to make?

6) A car 1.6t is supported by 4 gas shocks. If the weight is evenly distributed and each shock compresses 6cm, what is the spring constant for the CO gas in the shock?

PRACTICE MOMENTUM SHEET

1. A 3.0 kg puck traveling at 100 m/s on a frictionless surface strikes a second puck of 1.0 kg square on. Find (a) the combined final speed if they stick together.

(b) if the collision is perfectly elastic, their individual speeds if the pucks do not stick together.

2. A bullet of mass 10 g has a muzzle velocity of 300 m/s. Find (a) the momentum of the bullet

(b) the recoil velocity of the gun if its mass is 2.0 kg.

3. A 70 kg man dives away from a stationary canoe with a velocity of 3.0 m/s parallel to the water. If the canoe has a mass of 150 kg, find its recoil velocity.

4. A steel sphere of mass 0.10 kg is fired horizontally with a velocity of 30 m/s into a block of plasticine of mass 1.0 kg at rest. With what velocity does the combination move away?

5. If in the above question, a second sphere identical to the first hits the already moving combination in the same sense as the above, find the new combination velocity.

6. A bullet of mass 20 g fired at 200 m/s horizontally strikes a block of wood of mass 1.98 kg suspended from long inextensible mass less strings (at rest). If the combination sticks together find the velocity of the combination and determine how high it would swing. (Hint - think pendulum and energy).

Momentum Assignment.

1. A stationary Volkswagen Rabbit of mass 1.0 x 103 kg is rammed from behind by a Ford Escort of mass 1.2 x 103 kg, traveling at 20 m/s on an icy road. If they lock bumpers in the collision, how fast will the pair move forward?

2. A truck of mass 4500 kg moving at 10 m/s strikes the back of a car that is at rest. The car and occupants have a mass of 950 kg. (a) What is the speed of the car just after impact if the car and truck lock together? (b) If the impact lasts 0.3 s what is the average force on a 60 kg passenger in the car?

3. An atom of uranium disintegrates into two particles, one of which has a mass 60 times as great as the other. If the larger particle moves to the left with a velocity of 2.3 x 104 m/s. with what velocity does the lighter particle move?

4. On a frictionless air track, a 30 g glider moving to the right at 4.0 cm/s collides with an 80 g glider moving to the left at 1.5 cm/s. If the two gliders stick together in the collision, what is their final velocity?

5. A nucleus, initially at rest, decays radioactively. In the process, it emits an electron horizontally to the east, with momentum 9.0 x 10 -21kgm/s and a neutrino horizontally to the south, with momentum 4.8 x l0-25 kgm/s. (a) In what direction does the residual nucleus move?

(b) What is the magnitude of its momentum?

(c) If the mass of the residual nucleus is 3.6 x 10-25 kg, what is its recoil velocity?

6. The police report of an accident between...