Mechanics questions | form five Physics

An object of mass 2​ kg is attached to the hook of a spring balance which is suspended vertically to the roof of a lift. What is the reading on the spring balance when the lift is:

1. going up with the rate of 0.2​ ms^-2 ​
2. going down with an acceleration of 0.1​ms​^-2 ​
3. ascending with uniform velocity of 0.15​ ms ^-1

Answer / Solution

UNSOLVED

1. Define the term inertia.
2. Why is Newton’s first law of motion called the law of inertia?

Answer / Solution

UNSOLVED

A jet of water from a fire hose is capable of reaching a height of 20​m .​ If the cross sectional area of the hose outlet is 4.0×10​^-4​ m^2​ ​ , calculate the

1. Minimum speed of water from the hose.
2. Mass of water leaving the hose each second.
3. Force on the hose due to the water jet.

Answer / Solution

UNSOLVED

A boy ties a string around a stone of mass 0.15​ kg and then whirls it in a horizontal circle at constant speed. If the period of rotation of the stone is 0.4sec and the length between the stone and the boy’s hand is 0.50​ m ; ​

1. Calculate the tension in the string.
2. State one assumption taken to reach the answer in (i).

Answer / Solution

UNSOLVED

1. Define the term trajectory.
2. Briefly explain why the horizontal component of the initial velocity of a projectile always remains constant.

Answer / Solution

UNSOLVED