Question

an object is shot vertically upward into the air with an initial velocity of 20 m/s? which of the following correctly describes the velocity and acceleration of the object after 4seconds?

Answer 1

Answer:

Answer is (C)

Explanation:

For acceleration

• If the motion is vertically, then acceleration is 9.8 m/s²

» Upward motion, acceleration is negative (-9.8)

» Downward motion, acceleration is positive (+9.8)

For velocity

${ \rm{v = u + gt}} \\ { \rm{v = 20 + ( - 9.8 \times 4)}} \\ { \rm{v = - 19.2 \: m {s}^{ - 1} }}$