A body is moving along a straight line . It moves from a point P to Q in 15sec returns to a point R in 9sec . The distance between P and Q is 225m and that between Q and R is 81m. What are average velocity and average speed of the body in moving
(1) From P to Q and
(2) From P to Q and back to R
Answers
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Answer:
A body is moving along a straight line . It moves from a point P to Q in 15sec returns to a point R in 9sec . The distance between P and Q is 225m and that between Q and R is 81m. What are average velocity and average speed of the body in moving
(1) From P to Q and
Average velocity =
Average Speed =
(2) From P to Q and back to R
Average velocity =
Average speed =
Explanation:
Formula for calculating Average speed
Average speed = total distance travelled / total time taken
Formula for calculating velocity:
Velocity = Final displacement / total time taken
1) Average speed and velocity from P to Q
a) Average speed = total distance travelled / total time taken
Total distance between P and Q is 225 m
Total time taken from P to Q = 15s
Average Speed = 225 m / 15 s
= 15 m/s
b) Average velocity = displacement / time taken
Displacement from P to Q = 225m
Total time taken = 15 s + 9 s = 24s
Average velocity from P to Q = 225 m / 15s
= 15 m/s towards Q
2) Average speed and velocity from P to Q and back to R
a) Average speed = total distance travelled / total time taken
Total distance between P to Q and back to R
= 225m + 81 m
= 306m
Total time taken from P to Q and back to R
15s + 9s = 24s
Average Speed = 306 m / 24 s
= 12.75 m/s
b) Average velocity = displacement / time taken
Displacement from P to Q and back to R
= 225m - 81m = 144m
Total time taken from P to Q and back to R
= 15 s + 9 s
= 24 s
Average velocity from P to Q and back to R
= 144m / 24s
= 6 m/s towards P