A small coin of mass m1 is undergoing a uniform circular motion at a velocity v. The radius of the circular path is r. A piece of putty of mass m2 is dropped onto the coin. The new velocity of the coin-putty system is .

A. vB. m1v/m2C. m2v/m1D. m1v/(m1 +m2)E. m2v/(m1 +m2)

Answere is (D)

Explanation:

Given m1, v and m2

Total circular momentum is conserved: total circular momentum before putty coin collision is equal to total circular momentum after collision.

Let the final circular velocity of the system be V. Initial circular velocity of the putty is zero.

m1v + m2× 0 = (m1 + m2) V

V = m1v/(m1 + m2).

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me