Physics: time to reach shore, velocity of ice skaters, shuff

In the following problems, the answers are given. Show the working to arrive at the answers.

1. To get off a frozen, frictionless lake, a 65 kg person takes a 0.150 kg shoe and throws it horizontally, directly away from the shore with a speed of 2 m/s. If the person is 5 m from the shore, how long does he take to reach it?
Answer: - 1.08 x10^3 s = 18.1 min

2. Two ice skaters not paying attention collide in a completely inelastic collision. Prior to the collision, skater 1 with a mass of 60 kg, has a velocity of 5 km/h eastward, and moves at a right angle to skater 2, who has mass of 75 kg and a velocity of 7.5 km/h southward. What is the velocity of the skaters after the collision?
Answer: - 4.7 km/h at an angle of 62* south of east.

3. A moving shuffleboard puck has a glancing collision with a stationary puck of the same mass. If the friction is negligible, what are the speeds of pucks after collision? ...Vin = 0.95m/s
Answer: - V1 = 0.61 m/s and V2 = 0.73 m/s

4. In a high speed chase, a policeman's car bumps a criminal's car directly from behind to get his attention. The policeman's car is moving at 40 m/s to the right and has a total mass of 1800 kg. The criminal's car is initially moving in the same direction at 38 m/s. His car has a total mass of 1500 kg. Assuming an elastic collision, determine their two velocities immediately after the bump.
Answer: - Vp = 38.2 m/s, Vc = 40.2 m/s, both in same direction as initially moving.

5. Two cups are placed on the uniform board that is balanced on a cylinder. The board has a mass of 2 kg and is 2 m long. The mass of the cup 1 is 200 g and it is placed 1.05 m to the left of the balance point. The mass of the cup 2 is 400g. Where should the cup 2 be placed for balance (relative to the right end of the board)?
Answer: - 0.175m

Solution Summary

This posting contains solution to the given problems.

Two skaters are in the exact center of a circular frozen pond. Skater 1 pushes skater 2 off with a force of 100 N for 1.69 seconds. If skater 1 has a mass of 34 kg and skater 2 has a mass of 72 kg, what is the relative velocity (v1 - v2) after the push to the nearest hundredth of a m/s?
After reaching the other shore, how fas

A 500 N woman stands in the middle of a frozen lake of radius lOOm. The ice is frictionless so she can't walk. She decides to sacrifice one of her 0.5 kg shoes and throws it horizontally at 5 m/s. How long does it take her to reach the shore?

A dockworker applies a constant horizontal force of 80.0 N to a block of ice on a smooth horizontal floor. The frictional force is negligible. The block starts from rest and moves 11.0 m in 5.00 s.
a) What is the mass of the block of ice?
b) If the worker stops pushing at the end of 5.00 s, how far does the block move in th

Two friends, Al and Jo, have a combined mass of 168 kg. At an ice skating rink they stand close together on skates, at rest and facing each other, with a compressed spring between them. The spring is kept from pushing them apart because they are holding each other. When they release their arms, Al moves off in one direction at a

See attached file for full problem description with proper symbols.
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Two iceskaters, with masses of 50.0 and 75.0 , are at the center of a 40.0 -diameter circular rink. The skaters push off against each other and glide to opposite edges of the rink.
a.) If the heavier skater reaches the edge in 10.0, how long does

A river flows toward the east. Because of your knowledge of physics, you head your boat 38° west of north and have a velocity of 6.0 m/s due north relative to the shore.
(a) What is the velocity of the current?
(b) What is your speed relative to the water?

28-A 7.0 g bullet is fired into a 1.5 kg ballistic pendulum. The bullet emerges from the block with a speed of 200 m/s, and the block rises to a maximum height of 12 cm. Find the initial speed of the bullet?
18- A 730 N man stands in the middle of a frozen pond of radius 5.0 m. He is unable to get to the other side because o

A child in danger of drowning in a river is being carried downstream by a current that flows uniformly with a speed of 2.5 km/h. The child is 0.6 km from shore and 0.8 km upstream of a boat landing when a rescue boat sets out.
a) If the boat proceeds at its maximum speed of 20 km/h with respect to the water, what heading rela

Two ice skaters have masses m1 and m2 and are initially stationary. Their skates are identical. They push against one another and move in opposite directions with different speeds. While they are pushing against each other, any kinetic frictional forces acting on their skates can be ignored. However, once the skaters separate,