Answer:
(i) Average velocity = 0 m/s
(ii) Average speed ≈ 11.06 m/s
Step-by-step explanation:
To find the average velocity and average speed of the body, we need to understand the definitions of these two terms:
Average Velocity:
Average velocity is the displacement of an object divided by the time taken. Displacement is the change in position, which is a vector quantity, meaning it has both magnitude and direction.
Average Speed:
Average speed is the total distance traveled divided by the time taken. Unlike velocity, speed is a scalar quantity, meaning it only has magnitude and no direction.
Given information:
Radius of circular path (r) = 70 m
Half a revolution = 180 degrees (since a full revolution is 360 degrees)
Time taken (t) = 20 s
To calculate the average velocity and average speed, we'll need to determine the displacement and distance traveled by the body first.
Displacement:
For half a revolution, the body starts and ends at the same point on the circular path. Therefore, the displacement is zero because there's no net change in position.
Distance Traveled:
The distance traveled is the length of half the circumference of the circular path (since the body travels half a revolution). The formula for the circumference of a circle is 2πr, where r is the radius.
Distance = (1/2) × 2πr = πr
Now we can calculate the average velocity and average speed:
(i) Average Velocity:
Average velocity = Displacement / Time taken
Average velocity = 0 / 20 s = 0 m/s
(ii) Average Speed:
Average speed = Distance Traveled / Time taken
Average speed = (πr) / 20 s = (π × 70 m) / 20 s ≈ 11.06 m/s
So, the answers are:
(i) Average velocity = 0 m/s
(ii) Average speed ≈ 11.06 m/s