Question

A man is moving on his bike with 54km/hr. He takes a U-turn in 10s and continues to move with the same velocity. Find average acceleration during this time-
a) 3.0 m/s2 b) 1.5 m/s2 c) 0 d) -1.5 m/s2

Answer 1

Answer on Question #52074, Physics, Mechanics | Kinematics | Dynamics

A man is moving on his bike with $54\mathrm{km/hr}$. He takes a U-turn in 10 s and continues to move with the same velocity. Find average acceleration during this time-

a) $3.0\mathrm{m/s^2}$ b) $1.5\mathrm{m/s^2}$ c) 0 d) $-1.5\mathrm{m/s^2}$

Solution:

The acceleration is

$$a = \frac{v_f - v_i}{t}$$

In our case:

$$\begin{array}{l} v_i = 54 \frac{\mathrm{km}}{\mathrm{h}} = 15 \mathrm{m/s}, \\ v_f = 15 \mathrm{m/s}, \\ t = 10 \mathrm{s}, \\ \end{array}$$

Thus,

$$a = \frac{-15\tilde{i} - (15)\tilde{i}}{10} = -3\tilde{i}$$ $$|a| = 3 \mathrm{m/s^2}$$

Answer: a) $3.0\mathrm{m/s^2}$

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