Physics Answers

A 500 kg roller coaster is pulled to the top of a hill 45 m high and arrives at the top with a zero speed.

a) how much work has done by the vhain to pull the car to the top?

b) how much potential energy does it have at the top?

c)What is the total energy of the system?

d) how much kinetic energy does it have at the bottom?

A 25 kg child is sitting on a 10 kg sled. The child’s older sister is pulling the sled horizontally across the snow at a constant speed of 4 m/s by pulling on a rope with a force of 25 N at an angle of 30o above the horizontal. 

[4]   a.   Draw all appropriate diagrams for the situation. 

[3]   b.   Find the normal force acting on the sled. 

[3]   c.   Find the magnitude of the force of friction between the sled and the snow. 

At what distance from this particle does its field have a magnitude of 12.0 N/C

a baseball is thrown straight upward with a speed of 30 m/s. (a) How long will it rise? (b) How high will it rise? (c) How long after it leaves the hand will it return to the starting point? (d) When will its speed be 16 m/s?

A rectangular current-carrying wire loop which is free to rotate about a vertical axis in a uniform magnetic field of 1.42 T is rotating anti-clockwise. The current in the loop is 250 mA. The distance between a to b is 20 cm.

Determine the magnetic force exerted on a-b.

An electron is accelerated through a 100 V potential difference before perpendicularly entering a uniform magnetic field. Inside the field, the electron moves in circular trajectory of radius 4 cm, calculate the magnetic force that acts on the electron.

Two long parallel wires, P and Q are fixed on a horizontal plane in north-south direction. Wire P is 10 cm left of Q. Wire P carries 40 A current northwards while wire Q carries 20 A current downwards. Determine the magnitude and direction of the resultant magnetic field at midpoint between the wires.

A conducting cylinder of radius 3.25 cm and length 5.6 cm has a total charge of 4.5 x 10^-9 C distributed uniformly on its surface area. Find the potential at a) its surface, and b) 2.5 cm and c) 5.0 cm from the center of the cylinder.

a car slows down at -5.00m/s squared comes to a stop after 15 m what was the initial speed of the car.

the electrical resistance of the element in a platinum resistance thermometer at 100C, 0C and room temperature 75.000n, 63.000n and 64.000n respectively . determine the room temperature