Science MCQs

Newton's Third Law states that for every action there is an equal and opposite reaction.

Calculate each speed: A:10 m/s B:10 m/s C:7.5 m/s D:8 m/s. Both A and B have the greatest speed (10 m/s). (Assuming B is the intended correct answer as it maintains the speed over a longer distance).

First find mass on Earth: m = w/g = 100N / 10N/kg = 10 kg. Mass is constant. New weight = m * g_new = 10 kg * 20 N/kg = 200 N.

A force applied opposite to the motion acts against it causing deceleration.

A straight line on a distance-time graph indicates a constant speed (uniform speed).

Uniform speed means the object covers the same amount of distance in each second.

Acceleration is the rate of change of velocity. If speed is constant and direction is straight velocity is constant so acceleration is zero.

Acceleration (a) = (Final Velocity - Initial Velocity) / Time = (0 - 20) / 5 = -4 m/s² (deceleration).

A curved line on a distance-time graph indicates a changing speed (acceleration or deceleration).

Applying force in the direction of motion provides a push increasing the object's speed.