Question

test information
description: show all you work, including units, on separate paper. follow the \problem solving method\.
this final exam is cumulative and covers material from the entire course.
instructions: from the list of choices, select the one best answer.
multiple attempts not allowed. this test can only be taken once.
force completion this test can be saved and resumed later.
your answers are saved automatically.
question completion status:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
53 54 55 56 57 58 59 60 61 62
moving to another question will save this response.
question 37 of 62
1.6 points
save answer
a 0.10 kg rubber ball is falling straight down, and just before it strikes the ground, it is traveling at 12 m/s. the ball rebounds upward at 8.0 m/s. the collision with the floor lasts 0.040 s. what is the change in momentum of the ball?
1.2 kg·m/s
0.40 kg·m/s
0.80 kg·m/s
2.0 kg·m/s

Explanation:

Step1: Define Momentum and Direction

Momentum is \( p = mv \). Let downward be negative and upward be positive. Initial velocity \( v_i = -12 \, \text{m/s} \) (downward), mass \( m = 0.10 \, \text{kg} \), final velocity \( v_f = 8.0 \, \text{m/s} \) (upward).

Step2: Calculate Initial and Final Momentum

Initial momentum: \( p_i = m v_i = 0.10 \times (-12) = -1.2 \, \text{kg·m/s} \)
Final momentum: \( p_f = m v_f = 0.10 \times 8.0 = 0.80 \, \text{kg·m/s} \)

Step3: Calculate Change in Momentum

Change in momentum \( \Delta p = p_f - p_i = 0.80 - (-1.2) = 0.80 + 1.2 = 2.0 \, \text{kg·m/s} \)

Answer:

2.0 kg·m/s (corresponding to the option "2.0 kg·m/s")