Help With Assignment Questions (Forces)

[_Pistolkisses]

If anyone can give me any steps to take, or formulas to use when solving these I would REALLY appreaciate it. These ones have really stumped me.

1. Beavis and Butthead are out in space, or you may say "spaced-out". The force of attraction between them is 30N. Suddenly, Beavis takes a blue MEP (mass enhancing pill) and cuts his mass in half, and Butthead takes a green MEP and his mass triples. While they were doing this the distance between them doubled. What is the new force of attraction between them?

2. A tennis racket, in contact with a 55g ball for 0.0050 s, changes the ball's velocity from 30m/s [E] to 40m/s [W]. What is the average force exerted on the ball?

3. Two boxes of canned goods, 35 kg and 10 kg, are side by side on a frictionless surface. A horizontal force of 90N is applied to the 35kg box to move both both boxes. Determine the magnitude of the action and reaction forces between the two boxes.

4. The planet NUR has a radius of 2.4 x 10^6 m and a mass of 2.0 x 10^26 kg. How long would it take a 55kg NURD to hit the ground if he fell from a 30m high building?

Thanks.

 

[member 553083]

1. The new force of attraction between Beavis and Butthead can be calculated using the equation F = GMm/r^2, where G is the gravitational constant, M and m are the masses of Beavis and Butthead, and r is the distance between them. After the MEPs, M becomes 3M and m becomes M/2, so the new force of attraction is (6GM^2)/(4r^2).2. The average force exerted on the ball can be calculated using the equation F = mv/t, where m is the mass of the ball, v is the change in velocity, and t is the time of contact. The average force is (55g x 10 m/s) / 0.0050 s = 11,000 N.3. The magnitude of the action and reaction forces between the two boxes can be calculated using the equation F = mA, where m is the combined mass of the boxes (45 kg), and A is the acceleration of the system. Since the force applied to the 35kg box is 90N and the acceleration is 2 m/s^2, the magnitude of the action and reaction forces between the two boxes is 180 N.4. The time it would take a 55kg NURD to hit the ground if he fell from a 30m high building can be calculated using the equation t = √(2s/g), where s is the height of the building (30m) and g is the gravitational acceleration of the planet (9.8 m/s^2). The time is approximately 1.7 seconds.