Mechanics | Relativity Answers

a rubber ball of mass 50 g is thrown towards a vertical wall. it strikes the wall at a horizontal speed of 20ms-1 and bounces back with a horizontal speed of 18 ms-1 as shown below.

Take a hollow plastic ball using a needle pass a thread of about 105cm along a diameter of the ball. Tie a knot at one end. Hang the ball from a rigid support so that the ball is free too ascillate. Make a small hole in the ball near the top. Fill it with sand and find its time period of oscillations. Empty the ball and fill it with steel balls fillings and repeat the experiment. Similarly carry out the experiment with common salt. Compare the time periods obtained in the above three cases. What so you find?

If a = v^1/2, then at t =0 and at v = 0 find initial velocity(u) ?

There is a drawing of a mobile crane which is supported on the wheels at A and B. The weight of the base of the crane is 28 x 10^4 N.g is the centre of mass of the base.The Jib has a weight of 3x10^4 N uniformly distributed along its length. Fa is the total upwards force from the ground on the wheels at A when the crane is lifting a load of 15 x10 ^4 N. State how you would calculate the maximum load which the crane could support in this configuration without toppling. The answer is when Fa =0 but I don’t understand why ( this is from Ocr 2001)

An ice tube is kept on an inclined plane of angle 30degree . Coefficient of kinetic friction between block and inclined plane is 1 upon underroot 3 . What is the acceleration of block?

Water flows from a tube of radius r at velocity v, hits the wall perpendicularly and doesnt rebound
back. How much force does the water exert on the wall?

I think we are moving with speed more then that of light, So why our time is not stopped or it is stopped we don't even realize? (According to theory of Relativity of Time)

or Real Cosmic Time is even faster than we think?

Reason:
Our planet is revolving around sun at the speed of 108,000 km/h & simultaneously our sun is moving in the galaxy at the speed of 720,000 km/h even Milky way is moving in the Cluster (I don't know the speed). Our Local Cluster is moving at a very high speed. Our Laniakea Supercluster is moving across space & So on...

So Accordingly,

Our Speed = 108,000 km/h + 720,000 km/h + Speed of our Galaxy + Speed of our Cluster + Speed of our Super Cluster & So on...

If you want to send a gift to your friend on the other side of the earth digging a tunnel along
diameter, then determine how distance varies with acceleration.

A metal ball of mass 0.5kg is dropped from top of a vertical Clift of height 90m. When it hits the beach below it penetrates to a depth of 6.0cn calculate the average retarding force of the sand (neglect air resistance) I know the answer to this question is 7.5kN but I don’t understand how you get to answer

If the helicopter can fly with a cruise speed of Vx MPH and carry a mass of m kg explain how you would calculate the distance from the landing point that the helicopter would need to release the mass to land at the landing point assuming that the helicopter cruises at a height of h feet. State any equations that you would use.