Question

a 0.2 kg tennis ball moving at 10 m/s is hit by a racket, causing it to move in the opposite direction at -15 m/s. what is the magnitude of the impulse delivered by the racket? $j = m (v_f - v_i)$
options: 5 n·s, 0.5 n·s, 2 n·s, 1 n·s

Explanation:

Step1: Identify given values

$m=0.2\ \text{kg}$, $v_i=10\ \text{m/s}$, $v_f=-15\ \text{m/s}$

Step2: Apply impulse formula

Substitute values into $J = m(v_f - v_i)$
$J = 0.2\ \text{kg} \times (-15\ \text{m/s} - 10\ \text{m/s})$

Step3: Calculate the result

$J = 0.2 \times (-25) = -5\ \text{N·s}$; take magnitude $|J|=5\ \text{N·s}$

Answer:

5 N·s