Question

A ball is thrown vertically upwards with an initial velocity of 20 m/s. Calculate the time it takes for the ball to reach the highest point. (Assume \( g = 9.8 \, \text{m/s}^2 \))

• A. \( 2.04 \, \text{s} \)
• B. \( 1.8 \, \text{s} \)
• C. \( 3.0 \, \text{s} \)
• D. \( 4.0 \, \text{s} \)

Hint:

At the highest point, the velocity of a vertically thrown object becomes zero. The time to reach the highest point is simply the time taken for the velocity to reduce to zero under the influence of gravity.

Answer 1

The Correct Option is A

At the highest point, the velocity of the ball becomes zero. Using the equation of motion: \[ v = u + at \] Where: - \( v = 0 \, \text{m/s} \) (velocity at the highest point), - \( u = 20 \, \text{m/s} \) (initial velocity), - \( a = -g = -9.8 \, \text{m/s}^2 \) (acceleration due to gravity, acting downward). Rearranging the equation to solve for time \( t \): \[ 0 = 20 - 9.8 \times t \] \[ t = \frac{20}{9.8} = 2.04 \, \text{s} \] Thus, the time taken for the ball to reach the highest point is \( 2.04 \, \text{s} \).