Question

A car is moving along the circumference of the circle of radius r .

a) What is the distance travelled in one revolution ?

b) What is the displacement in half revolution ?

c) What does the speedometer of the car measure ?

d) Can a body have acceleration without velocity , Give example.
​

Answer 1

Answer:

Displacement is the minimum distance between the start and end point. Hence, the displacement in this case will be the diameter of the circle, i.e., 2R.

Distance is the length of path covered by the particle/object. Here, the distance will be πR.

Therefore, the ratio of displacement to distance is 2:π

Explanation:

HOPE THIS HELP YOU MATE

Answer 2

Given,

A car is moving along the circumference of the circle of radius r.

To Find,

1. The distance travelled in one revolution.
2. The displacement in half revolution.
3. The measure of the speedometer of the car.
4. Whether a body can have acceleration without velocity with example.

Solution,

$\setlength{\unitlength}{1cm}\begin{picture}(0,0)\thicklines\qbezier(2.3,0)(2.121,2.121)(0,2.3)\qbezier(-2.3,0)(-2.121,2.121)(0,2.3)\qbezier(-2.3,0)(-2.121,-2.121)(0,-2.3)\qbezier(2.3,0)(2.121,-2.121)(-0,-2.3)\put(0,0){\line(1,0){2.3}}\end{picture}$

a) The distance travelled in one revolution is the circumference of the circle.

Therefore, the answer is-

2πr

b) Displacement refers to the shortest distance between the starting and ending point. As we have to find the displacement when the car completes half a revolution, it is the diameter of the circle-

2r

c) As the name suggests, the speedometer measures as well as shows the driver the instantaneous speed of the car. Instantaneous speed refers to the speed of a body at a particular moment.

d) Yes, a body can have acceleration without velocity. For example:

When a an object is thrown upwards, and it reaches its maximum height, there is no velocity but there is acceleration due to gravity.