Topic: Engineering Mechanics
A car moving with uniform acceleration covers 450 m in a 5 second interval, and covers 700 m in the next 5 second interval. The acceleration of the car is
- A. $7~m/s^{2}$
- B. $50~m/s^{2}$
- C. $25~m/s^{2}$
- D. $10~m/s^{2}$
Answer: D. $10~m/s^{2}$
Explanation: Using $s=ut+\frac{1}{2}at^{2}$. At $t=5~sec$, $s=450~m$, so $450 = 5u + 12.5a \implies 900 = 10u + 25a$ (Eq. 1). At $t=10~sec$, $s=450+700=1150~m$, so $1150 = 10u + 50a$ (Eq. 2). Subtracting Eq. 1 from Eq. 2 gives $250 = 25a \implies a = 10~m/s^{2}$.