Physics Answers

Compute the electric force between two charges of 5×10-9 C and -3×10-8 C which are separated by r=10 cm

A 10 cm object is located 15 cm from the concave mirror with the focal length of 5 cm. An Image  7 cm from the mirror is detected, find its height

A point charge of 16 uc is placed in the centre of a conductive shell carrying a charge of -8 uc. What are the charges on the inner and outer surfaces of the shell?

You are standing on the sci.com. building 46.0 m high above the ground. Your classmate, 1.8 m tall, is walking alongside the building at a constant speed of 1.20 m/s. If you wish to drop an egg onto his head,

a) where should he be when you release the egg? Assume that the egg is in free fall.

b) what will be the velocity of the egg when it hits his head?

A car heading east through a city accelerates after passing a signpost marking the city limits. It is accelerating at

constant magnitude of 3.0 m/s2. At time t = 0 the car is 5.0 m east of the signpost, moving east at 15 m/s. a) Find the car’s position at t=2.0 s.

b) Find the car’s velocity at t=2.0 s.

c) Where is the car when its velocity is 25 m/s.

If a student jumps straight up to a height of 0.440m, what is his initial speed as it leaves the ground? How long

is he in the air?

A car is stopped at the traffic light. It then travels along a straight road so that its distance from the light is given by 𝑥(𝑡) = 𝑏𝑡2 − 𝑐𝑡3 where b=2.40 m/s2 and c=0.120 m/s3.

a) Calculate the average velocity of the car for the time interval t=0 to t=10.0 s.

b) Calculate the instantaneous velocity of the car at t=0 and t=10.0s

c) How long after starting again from rest is the car again at rest.

“A train of mass 120,000 kg is moving with velocity of 10m/s and is acted upon by a forward force of 7000 N due to engine and frictional force of 750 N. What will be the velocity of the train after 1,000 seconds?”

A spherical conductor of radius 8 cm has a uniform surface charge density of 0.1 nC/m^2. Determine the electric field: a) on the surface of the conductor; b) at a distance of 10 cm from the centre of the conductor.

A hockey player makes a slap shot, exerting a

force of 37.2 N on the hockey puck for 0.147 s.

What impulse is given to the puck?

Answer in units of kgm/s.