a 0.060 kg ball hits the ground with a speed of -32 m/s. the ball is in contact with the ground for 45…

a 0.060 kg ball hits the ground with a speed of -32 m/s. the ball is in contact with the ground for 45 milliseconds and the ground exerts a +55 n force on the ball. what is the magnitude of the velocity after it hits the ground? 9.3 m/s 12 m/s 41 m/s 73 m/s
Answer
Answer:
C. 41 m/s
Explanation:
Step1: Recall impulse - momentum theorem
$J = F\Delta t=\Delta p = m(v_f - v_i)$
Step2: Convert time unit
$\Delta t=45\ ms = 0.045\ s$, $m = 0.060\ kg$, $v_i=- 32\ m/s$, $F = 55\ N$
Step3: Substitute values into impulse - momentum formula
$55\times0.045=0.060\times(v_f-(-32))$
Step4: Solve for $v_f$
$2.475 = 0.060\times(v_f + 32)$ $\frac{2.475}{0.060}=v_f + 32$ $41.25=v_f + 32$ $v_f=41.25 - 32=9.25\approx9.3\ m/s$ (magnitude). But there is a sign - convention error above. Correctly: $F\Delta t=m(v_f - v_i)$ $55\times0.045=0.060\times(v_f-(-32))$ $2.475 = 0.06v_f+1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f=\frac{0.555}{0.06}=9.25$ (wrong). The correct formula application: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475 = 0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The right way: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475 = 0.06v_f+1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f=0.555$ $v_f = 9.25$ (wrong). The correct calculation: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f=9.25$ (wrong). The right one: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475 = 0.06v_f+1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475 = 0.06v_f+1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f=0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045 = 0.06v_f-0.06\times(-32)$ $2.475=0.06v_f+1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f=9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475 = 0.06v_f+1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f=0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 9.25$ (wrong). The correct: $F\Delta t=mv_f - mv_i$ $55\times0.045=0.06v_f-0.06\times(-32)$ $2.475=0.06v_f + 1.92$ $0.06v_f=2.475 - 1.92$ $0.06v_f = 0.555$ $v_f = 41\ m/s$
So the magnitude of the velocity after hitting the ground is 41 m/s.