Question

A toy racing car is moving with constant speed around a circle. When it is at a point A, its coordinates are x=0, y=3m and its velocity is 6m/s (along the x-axis). When it is at point B its velocity and acceleration are:

Answer 1

Hint: The quantity speed does not have a direction but velocity is a vector. Therefore, first we need to find the direction of the velocity of the car. Once we know the direction of the velocity at A, we can find it at point B. The acceleration is the change in velocity per unit time.

Complete answer:
It is given in the question that the toy car is moving on a circular path. At the point A the velocity is given as 6m/s along the x-axis. As a negative sign is not given, we’ll assume it is positive. This means that the car is moving in a clockwise direction.
As the car is moving in clockwise direction the velocity at the point B will be along the positive y-axis.
It is mentioned in the problem that the toy car is moving at constant speed. Thus, the velocity at point B will be 6m/s, along the positive y-axis.
Since the velocity is constant the acceleration will be zero, as the rate of change of velocity is acceleration. And there is no change in acceleration.
Therefore, at the point B the velocity of the car is 6m/s along the y-axis and the acceleration is zero.

Note:
The quantity, velocity is a vector analogous to speed, which is a scalar. Velocity is the rate of change of displacement with respect to time. While speed is the distance travelled per unit time. In the above problem they’ve given constant speed. But we found the direction by assuming the direction to be positive via assuming the car to be rotating in the clockwise direction.