Directions:
There 20 multiple choice questions. Each question is 5 points, and the exam is 100 points. The exam is open book, open notes. However, you may not discuss the exam with your classmates.
Submit your work for each question in Canvas.
𝐾𝐸 = 1
2 𝑘𝑣2, 𝑈𝑔 = 𝑚𝑔ℎ , 𝑈𝑠 = 1
2 𝑘𝑥2 , 𝑊 = 𝐹𝑑 , 𝐸 = 𝐾𝐸 + 𝑈𝑔 + 𝑈𝑠 ,
𝐸𝑖 ± 𝑊𝑛𝑐 = 𝐸𝑓 , 𝑃 = 𝑊
𝑡 , 𝐸 = 𝑃𝑡 , 𝑔 = 9.8 𝑚
𝑠𝑒𝑐2 ,
𝑝⃗ = 𝑚 𝑣⃗ , 𝐾𝐸 = 1
2 𝑘𝑣2, 𝑣⃗1,𝑖 − 𝑣⃗2,𝑖 = −(𝑣⃗1,𝑓 − 𝑣⃗2,𝑓), 𝑎 = 𝑣𝑒
𝑚
Δ𝑚
Δ𝑡 − 𝑔
Problems 1-2 refer to the following situation. A ball is released from rest from a height of 3.0 m
above the ground.
Problem 1:
What is the speed of the ball when the ball is 2.0 m above the ground?
a. 1.4 m/sec b. 2.4 m/sec c. 3.4 m/sec d. 4.4 m/sec
Problem 2:
What is the speed of the ball just before the ball hits the ground?
a. 5.7 m/sec b. 6.7 m/sec c. 7.7 m/sec d. 8.7 m/sec
Problems 3-4 refer to the following situation. A computer consumes 0.200 kW of power.
Problem 3:
What how much energy does the computer consume in 30 days if the computer is used 6 hours
each day?
a. 36.0 kW⋅hr b. 46.0 kW⋅hr c. 56.0 kW⋅hr d. 66.0 kW⋅hr
Problem 4:
What is the cost of running this computer if the electricity costs $0.120 per kW⋅hr?
a. $1.32 b. $2.32 c. $3.32 d. $4.32
Problems 5-6 refer to the following situation. A person of mass 60 kg starts from rest. The
person goes up a flight of stairs of height 3.0 m and the person has a speed of 2.0 m/sec when
they reach the top of the stairs.
Problem 5:
What is the work done by the person to reach the top of the stairs?
a. 1884 J b. 2084 J c. 2284 J d. 2484 J
Problem 6:
What is the power output of the person If it took the person 3.50 sec to reach the top of the
stairs?
a. 238.3 W b. 338.3 W c. 438.3 W d. 538.3 W
Problems 7-8 refer to the following situation. A person of mass 90.0 kg starts from rest. The
person runs 200.0 m in 50.0 sec on a level road. The final speed of the person is 4.0 m/sec and a
wind exerts an average force of 3.0 N against the person.
Problem 7:
What is the work done by the person?
a. 1120 J b. 1320 J c. 1520 J d. 1720 J
Problem 8:
What is the power output of the person?
a. 16.4 W b. 26.4 W c. 36.4 W d. 46.4 W
Problems 13-16 refer to the following situation (shown in the figure below). A mass
𝑚1 = 2.3 𝑘𝑔 is moving to the right with an initial speed 𝑣1,𝑖 = 1.6 𝑚/𝑠𝑒𝑐 and a mass
𝑚2 = 0.70 𝑘𝑔 is moving to the right with an initial speed 𝑣2,𝑖 = 0.60 𝑚/𝑠𝑒𝑐. 𝑚1 and 𝑚2 then
collide. After the collision, 𝑚2 moves to the right with a speed 𝑣2,𝑓 = 1.9 𝑚/𝑠𝑒𝑐.
Problem 13:
What is the kinetic energy of the two-mass system before the collision?
a. 1.1 J b. 2.1 J c. 3.1 J d. 4.1 J
Problem 14:
What is the speed and direction of 𝑚1 after the collision?
a. 1.2 m/sec to
the left
b. 2.2 m/sec to
the left
c. 1.2 m/sec to
the right
d. 2.2 m/sec to
the right
Problem 15:
What is the kinetic energy of the two-mass system after the collision?
a. 1.9 J b. 2.9 J c. 3.9 J d. 4.9 J
Problem 16:
What type of collision did 𝑚1 and 𝑚2 have?
a. Completely Inelastic b. Inelastic c. Elastic
Problems 17-20 refer to the following situation (shown in the figure below). A mass
𝑚1 = 1.2 𝑘𝑔 is moving to the right with an initial speed 𝑣1,𝑖 = 2.6 𝑚/𝑠𝑒𝑐 and a mass
𝑚2 = 1.8 𝑘𝑔 is moving to the right with an initial speed 𝑣2,𝑖 = 1.1 𝑚/𝑠𝑒𝑐. 𝑚1 and 𝑚2 then
collide. After the collision, 𝑚2 moves to the right with a speed 𝑣2,𝑓 = 1.7 𝑚/𝑠𝑒𝑐.
Problem 17:
What is the kinetic energy of the two-mass system before the collision?
a. 5.1 J b. 6.1 J c. 7.1 J d. 8.1 J
Problem 18:
What is the speed and direction of 𝑚1 after the collision?
a. 1.2 m/sec to
the left
b. 1.7 m/sec to
the left
c. 1.2 m/sec to
the right
d. 1.7 m/sec to
the right
Problem 19:
What is the kinetic energy of the two-mass system After the collision?
a. 1.3 J b. 2.3 J c. 3.3 J d. 4.3 J
Problem 20:
What type of collision did 𝑚1 and 𝑚2 have?
a. Completely Inelastic b. Inelastic c. Elastic