Physics Answers

A crane is used to lift some building materials which weigh 112 kg from the ground to the top of a building.

If the building materials are being raised by an electrical winch at a speed of 2.13 m s−1 then at what rate is the winch using electrical power? (in W to 3 s.f)

note: use g = 9.81 m s−2.

xygen ( molecular weight 32) is compressed reversibly and polytropically in a

cylinder from 1.05 bar, 15oC to 4.2bar in such a way that one- third of the work input

is rejected as heat to the cylinder walls . calculate the final temperature of the oxygen.

Assume oxygen to be aperfect gas and take Cv = 0.649kJ/kg.K

A long straight wire carries a current of 1.0 A.

(a) At what distance from the wire is the magnitude of the magnetic field

equal to 2.5 x 10^-5 T?

(b)What is the magnitude of the magnetic force that this wire will exert on a

3.0 nC particle moving at 4.2 x 10^4 m/s perpendicular to the field at that

distance?

A 55.0 m wire carries a current of 2.25 A in a location where Earth’s

magnetic field is 4.5 x 10^-3 T. The wire experiences a force of 0.15 N. Find

the angle between the wire and the magnetic field.

starting from rest, a train is uniformly accelerated and reaches a velocity of 20km/h after 15cesconds. what is its acceleration

A student who is standing 0.5 meters from a plane mirror moves at a velocity of 0.75 

meters per second for 3 seconds away from the mirror. How much further is the student 

from her image than when she first started moving?

A 75 kg man is riding an escalator in a shopping mall.The escalator moves the man at a constant velocity from ground floor level to the floor above,a vertical height of 4.60m.What is work done by a,the gravitational force and b,by the escalator

an oscillating body takes 0.8 seconds to complete four cycles. What is the period, frequency, and angular frequency of the body

The Bob of a simple pendulum oscillates with an amplitude of 20 cm. If the acceleration of the Bob is - 4y, where y is the displacement, calculate the

(I) magnitude of its maximum acceleration.

(II) period of the motion

(III) magnitude of the maximum velocity

A 480g sample of thallium-208 has a half-life of 3.053 minutes.What fraction of the parent material will remain after 12.212 minutes?