Mechanics | Relativity Answers

Draw a graph showing the relationship between acceleration and net force

If a gymnast sitting on a stool with his arms stretched lower his arms then what happened with angular speed

Three weights W1, W2 and W3 are connected by a light inextensible string which passes over a fixed pulley at C. The weight W3 is freely hanging at D and the system is kept in equilibrium by a horizontal force P applied at A. If AB and BC are making angles Q and H respectively with the horizontal then prove that
tan Q = W3/[square root{ W3^2 - (W1 + W2)^2}]

A spider crawling across a table leaps onto a magazine blocking its path. The initial velocity of the spider
is 0.870 m/s at an angle of 35.0o
above the table, and it lands on the magazine 0.0770 s after leaving the
table. Ignore air resistance. How thick is the magazine? Express your answer in millimeters.
Expert's answer

a car acceleretes uniformly from 0 to 72 km/hr in 11.5 seconds what is the acceleration of the car in m/s2

a body whose moment of inertia is 3.0 kg/m2 is at rest. It rotated for 20 s by a torque of 6.0 Nm. Calculate the (i) angulardisplacement of the body in 20 s. (ii) angularmomentum of the body at 20 s. Is the angular momentum of the body constant ?„explain.(iii) work done by the torque.

A spider crawling across a table leaps onto a magazine blocking its path. The initial velocity of the spider
is 0.870 m/s at an angle of 35.0o
above the table, and it lands on the magazine 0.0770 s after leaving the
table. Ignore air resistance. How thick is the magazine? Express your answer in millimeters.

crate is moved across the floor by pulling a
rope tied to it. The force on the crate is of
magnitude 450 N and is directed at an angle
of 60° to the horizontal. The force of friction
on the crate is 125 N. The mass of the crate is
300 kg. Draw the free body diagram for the
system and calculate the acceleration of the
crate. Calculate the work done by each of the
forces in 'displacing the crate by 5.0 m. Which
of these forces is a "no-work" force ?

At a crossing a truck travelling towards the north collides with a car travelling towards
the east. After the collision the car and the truck stick together and move off at an angle
of 30 º east of north. If the speed of the car before the collision was 20 ms−1, and the
mass of the truck is twice the mass of the car, calculate the speed of the truck before
and after the collision

A small projectile of mass m moves with speed v to the right. The projectiles strikes and sticks to the end of a stationary bar of mass M, legth L, pivoted about a frictionless axle through its centre. Derive an expression for the angular velocity of the system immediately after the collision