Mechanics | Relativity Answers

Apparent Weight You take a ride in a fast
elevator to the top of a tall building and ride
back down. Compare your apparent and real
weights at each part of the journey. Sketch
free-body diagrams to support your answers.

A car negotiate a bend of radius 20m with an acceleration of 12m/s². What is the maximum speed of the car attained without skipping?

A space explorer travels from planet α to planet µ at a speed of 0.37 c. When she is precisely halfway between
the planets, a distance of 1 light-week from each in the planets’ frame, nuclear devices are detonated on
each planet. The explosions are simultaneous in the frame of the planets. What is the difference in time of
arrival of the flashes from the explosions as observed by the space explorer?

A 50-gm mouse falls onto the outer edge of a phonograph turnable of radius of 20cm rotating at 33 rev/min. How much work it does to walk into the center post? Assume that the angular velocity of the turnable does not change.

A flagpole weighs 53kg with a flag. The flagpole is 8.4 m long. The flagpole is attached to the wall partly at point A and partly with a horizontal line extending from the top end of the flagpole. The center of gravity of the flagpole and flag is in the bar 5.0 m from the point A. The angle between the bar and the wall is 45 degrees as the figure shows.
Determine the power of the cable.

A roller coaster cart with a mass of 1283 kg starts on a hill that is 189 m off the ground. The hill descends all the way to the ground, before going back up hill. How fast is the roller coaster going when it reaches the ground?

A 0.010 kg arrow is fired from a bow whose string exerts a force of 110 N on the arrow over a distance of 0.80 m. What is the SPEED of the arrow as it leaves the bow?

A 75 kg bobsled is pushed along a horizontal surface by two athletes. After the bobsled is pushed a distance of 5.0 m starting from rest, its speed is 6.0 m/s. Find the NET FORCE on the bobsled.

A student wearing frictionless roller skates on a horizontal surface is pushed by a friend with a constant force of 50.0 N. How FAR must the student be pushed, starting from rest, so that her final kinetic energy is 350 J?