Physics Answers

The car screw Jack is used to lift a car whose weight is 8800N.The bar for rotating the jack is 0.21m long and pitch of the screw is 2 mm. Calculate the effort required to operate the screw Jack assuming 50% efficient. If the bar is rotated 10 times how far will the car be raised? Hence, calculate the work done in raising the car through this distance.

A dielectric object is placed in an electric field. The object becomes polarised and 

a large number of atomic/molecular dipoles in the object align in the direction of 

the applied electric field. Derive an expression for the electric potential due to this 

polarised dielectric at a point outside the dielectric.

A transformer steps down 220V Ac to 12V AC. Using suitable circuitsincorporating PN diodes

i.Half wave rectified signal [10]

explain how each of the following signals can be obtained

ii.Full Wave Bridge rectified signal.

A metal bar 50cm long at 15°c is heated to 85°c. If it expands by 0.088cm, determine its linear expansivity.

A galvanometer with a resistance of 15.0Ω gives a full-scale reading for current of 3.0 A. What shunt resistance is needed to convert this into an ammeter with a 30.Ω A full-scale reading?

If a school bus moves 1600 meters at an average speed of 12 m/s, how long did the journey take?

Explain symmetric and antisymmetric function using three identical particles

When a glass is rubbed with a silk cloth, the rod acquires a charge of magnitude 3.45 nC. (a) Did the glass rod gain or lose electrons/ (b) How many electrons were transferred during the process? (c) What is the change in the mass of the glass rod? (d) What is the change in the mass of the silk cloth?

A 0.0450-𝑘𝑔 golf ball initially at rest is given a speed of 25.0 𝑚/𝑠 when a club strikes it. If the club and ball are in contact for 2.00 𝑚𝑠, what average force acts on the ball? Is the effect of the ball’s weight during the time of contact significant? Why or why not?

determine the magnitude of an electric field at r=0.01m from the center of non-conducting sphere with a radius R=0.001 possessing a charge of 7C which evenly distributed throughout the sphere. (r>R).