Question

A car moving with constant acceleration covers the distance between two points 114 metres apart in 11 seconds. Its speed as it passes the second point is 13 m/s.
What is the speed (to 1 decimal place) at the first point?

Answer 1

Answer on Question #69352 -Physics / Other

A car moving with constant acceleration covers the distance between two points $S = 114$ metres apart in $t = 11$ seconds. Its speed as it passes the second point is $v = 13 \, \text{m/s}$. What is the speed $u$ (to 1 decimal place) at the first point?

Solution

The distance

$$S = \frac{u + v}{2} t.$$

Thus, the speed $u$ at the first point

$$u = \frac{2S}{t} - v = \frac{2 \times 114}{11} - 13 = 7.7 \, \frac{\text{m}}{\text{s}}.$$

Answer: $7.7 \frac{\text{m}}{\text{s}}$

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