Physics Answers

A spot car skids off of a wet mountain at 48.5 m/s and lands in the river, 110 m below the road. How long will it take for the sports car to land in the water

Four identical point charges (q = + 10.0 microCoulombs) are located on the corners of a rectangle as shown in Figure P23.9. The dimensions of the rectangle are L = 60.0 cm and W = 15.0 cm. Calculate the magnitude and direction of the net electric force exerted on the charge at the lower left corner by the other three charges.

The electric potential immediately outside a charged conducting sphere is 200 V, and 10.0 cm farther from the center of the sphere the potential is 150 V. Determine (a) the radius of the sphere and (b) the charge on it. The electric potential immediately outside another charged conducting sphere is 210 V, and 10.0 cm farther from the center the magnitude of the electric field is 400 V/m. Determine (c) the radius of the sphere and (d) its charge on it. (e) Are the answers to parts (c) and (d) unique?

A cylindrical shell of radius 7.00 cm and length 2.40 m has its charge uniformly distributed on its curved surface. The magnitude of the electric field at a point 19.0 cm radially outward from its axis (measured from the midpoint of the shell) is 36.0 kN/C. Find (a) the net charge on the shell and (b) the electric field at a point 4.00 cm from the axis, measured radially outward from the midpoint of the shell.

A force of 300 N acts on a 2.5 m long and 10 kg rod initially at rest. what is the final angular momentum of the rod if the force acts on it for 8 seconds?

A +200 uC charge is placed at the origin. A +400 uC charge is placed at 2m above the origin(y-axis), and a -600 uC charged is placed 3m to the right of the origin (x-axis). What is the magnitude and direction of the net force acting on the charge placed at the origin?

A 75.0 kW, 230-V shunt generator has a generated emf of 243.5 V. If the field current is 12.5 A at
rated output, what is the armature resistance? (Ans. 0.0399).

A rocket and payload are moving through space with a constant velocity of 5000 m/s relative to the Earth. The mass of the rocket is 4000 kg and the mass of the payload is 1000 kg. The rocket and payload are then separated by a spring that pushes them apart so that they have a relative velocity of 100 m/s.

What are the velocities of the rocket and payload relative to the earth after separation?
What is the change in kinetic energy before and after the separation?
The spring that separated the rocket and payload has a spring constant of 4.0 x 106 N/m. How much was the spring compressed before separation?
What was the maximum force of the spring on the rocket?

A conical shaped tank of height H and width W is placed above a spherical water tank of radius R. Water drains from the conical tank into the spherical tank through a small opening of radius r. Similarly, the spherical tank empties though a small opening of radius r located at its bottom. Find the time it would take to drain both the tanks.

Imagine a space elevator with m = 30 kg/m extending from the surface (6400 km) to the geosynchronous height of 40,000 km. Take g to be changing with the height. If a stray satellite hits the top of the elevator find the time that the wave will take to reach the surface. The answer should be a few hours or so.