Question

An object with a mass 10 kg moves at a constant velocity of 10 m/sec. A constant force then acts for 4 second on the object and gives it a speed of 2 m/sec in opposite direction. The acceleration produced in it, is

• A. $3m/\sec^{2}{}$
• B. $- 3m/\sec^{2}{}$
• C. $0.3m/\sec^{2}{}$
• D. $- 0.3m/\sec^{2}{}$

Answer 1

Answer: (B)

$- 3m/\sec^{2}{}$

Answer 2

$\overrightarrow{a} = \frac{\overset{\rightarrow}{v_{2}} - \overset{\rightarrow}{v_{1}}}{t} = \frac{( - 2) - ( + 10)}{4} = \frac{- 12}{4} = - 3\mspace{6mu} m/s^{2}$