Mechanics | Relativity Answers

1) a 6 kg cart on a level surface is pulled at a constant velocity of 2 m/sec by a constant force of 10 N . what is the acceleration? what is the friction force opposing the motion ?


2) A hot air balloon (with bucket) has a mass of 900 kg . the balloon has a buoyant force upward of 12,000 N and a westward wind force of 500 N . Find the acceleration of the balloon . What is the force of gravity (weight) of the balloon and bucket ?

A car drives with a constant acceleration of 6.0 m/s2. If it begins with a velocity of 8.0 m/s, and travels a displacement of 120 m, how much time will this elapse?

Two spacecraft are 13,500 m apart and moving directly toward each other. The first spacecraft has velocity 525 m/s and accelerates at a constant −15.5 m/s2. They want to dock, which means they have to arrive at the same position at the same time with zero velocity. What would the average acceleration of the second spacecraft be in m/s2? Hint: Use the first spacecraft to get needed information for the second spacecraft remembering that the time is the same for both and their total distance is 13,500 m. Assume the second spacecraft to have a positive initial velocity. Include a sign with your answer.

A turntable is designed to acquire an angular
velocity of 33.5 rev/s in 0.5 s, starting from
rest.
Find the average angular acceleration of th
turntable during the 0.5 s period.
Answer in units of rad/s

A fizzy drink can bobs up and down in water due to waves travelling across the surface. The waves travel at 0.7ms-1 and have a wavelength of 0.5m and an amplitude of 0.1m. Calculate the maximum velocity of the can?

A pupil attached a rubber band to a door handle and pulled it until it opened. She measured the distance the band stretched and found this to be 2.5 cm. What was the size of the force she applied to open the door?

A .72 kg arrow is pulled back in a bow and pointed straight up into the air. The arrow has 162 J of elastic potential energy. How fast will the arrow be moving when it is released from the bow?

A skater has a moment of inertia of 150 kgm2 when his arms are outstretched and a moment of inertia of 60 kgm2 when his arms are tucked in close to his chest. If he spins at an angular speed of 2.0 rps (revolutions per second) with his arms outstretched, what will his angular speed be when they are tucked in?

A 10kg solid sphere of radius 0.5m is rotated about an axis through its center. If the sphere accelerates from rest to an angular speed of 3.0 rad/s while rotating 2.0 revolutions, what net torque is required?

The pedals of a bicycle rotate in a circle with a diameter of 50cm. What is the maximum torque a 75kg rider can apply by putting all of her weight on one pedal?