Physics Answers

A car is moving around a banked curve of radius 86 m at a constant speed. The road is banked at an angle of 11° and the car is moving at just the correct speed to ensure that there are no lateral frictional forces on the tyres - that is the only forces acting on the car are the force of gravity and the normal force from the road.

At what speed is the car moving? (in m s−1 to 2 s.f)

A person swings a 350 g ball around their head on a string as shown in the figure above.

The tension in the string is 10 N and the ball moves in a circle of radius 0.93 m at a constant speed of 5.0 m s−1.

What is the angle θ that the string makes with the horizontal? (in ° to 2 s.f)

A reckless hunter is on a boat which is stationary in the middle of a lake.

They fire their gun horizontally 10 times. Each time they fire, a 12 g bullet leaves the gun at a speed of 410 m s−1.

What is the speed of the boat after they have have finished firing their gun if the total mass of the boat, hunter, and gun is 150 kg? (in m s−1 to 2 s.f)

Assume no drag forces from the water.

A spring with a spring constant of 6.2 N m−1 is used to launch a 5.0 g slider along a frictionless track as shown in the figure above. The spring is compressed by 16 cm.

To what height h above the height labeled 0 m in the figure does the slider reach? (in m to 2 s.f)

A proton moves through a uniform magnetic field of magnitude 2.0 μT = 2.0

x 10^-6 T at a speed of 5.00 x 10^6 m/s.

(a) What is the magnitude of maximum

magnetic force it can experience?

(b) If the proton is replaced by an electron,

will it experience the same maximum force?

A charge of 6x10^-7C is transferred from infinity to point A. If the work done to do this is 1.2x10^-5J what is the potential point A

What should be the length of an ideal solenoid consisting of 1250 turns for

the magnetic field in its interior to be 0.025 T?

A current of 2.0 A is flowing

through the solenoid.

Two parallel wires are separated by a distance of 0.05 m. Wire 1 carries a

carries current of 12.0 A. Wire 2 carries a current of 6.0 A flowing in the

opposite direction as shown in the illustration.

Find the

(a) magnitude and

direction of the magnetic field created by wire 1 at wire 2,

(b) force exerted

by wire 1 on the 2.0 m long section of wire 2, and

(c) force exerted by wire 2

on wire 1.

A 2.0 centimeter tall object id placed 30.0 centimeters from a concave mirror. The focal length of the mirror is 10.0 centimeters. (a) where is thr image seen? (b) how tall is the image? 

Three 45-Ω lightbulbs and three 75-Ω lightbulbs are connected in series. (a) what is the total resistance of the circuit? (b) what is their resistance if all six are wired in parallel? (c) Show the circuit illustration.