Galaxy_Fireworks
Jan 29, 2008, 06:12 PM
Please could you help me with these problems..Thanks in advance for your help.
14.) A person moves a large box across a level floor by applying a horizontal force of 300 N. If the person pushes the box a distance of 6 meters in 10 seconds, how much work does the person do on the box?a. 180 joules b. 200 joules c. 1800 joules d. 18000 joules
15.) A 10-kilogram ball is fired with a velocity of 500 meters per second from a 1,000 kilogram cannon. What is the recoil velocity of the cannon?a. 5 m/sec b. 2 m/sec c. 10 m/sec d. 500 m/sec
16.) A 120 kg lineman moving right at 2 m/s tackles an 80 kg football fullback moving left at 8 m/s. After the collision, both players move left at 2 m/s. What is the momentum of the players after the collision?
a. momentum of lineman= 240 kg m/s and momentum of fullback =160 kg m/s
b. momentum of lineman=240 kg m/s and momentum of fullback= 640 kg m/s
c. momentum of lineman= 720 kg m/s and momentum of fullback= 320 kg m/s
d. momentum of lineman= 400 kg/m/s and momentum of fullback= 400 kg m/s
17.) A baseball player throws a ball horizontally. Which statement best describes the ball's motion after it is thrown? (neglect the effect of friction)a. It's vertical speed remains the same, and its horizontal speed increases
b. It's vertical speed remains the same, and its horizontal speed remains the same
c. It's vertical speed increases, and its horizontal speed increases
d. It's vertical speed increases, and its horizontal speed remains the same
18.) An object falls freely near the Earth's surface. Which best represents the relationship between the object's kinetic energy and its time of fall?a. Kinetic energy increases at a constant rate
b. Kinetic energy decreases at a constant rate.
c. Kinetic energy decreases by time squared
d. Kinetic energy increases by time squared
14.) A person moves a large box across a level floor by applying a horizontal force of 300 N. If the person pushes the box a distance of 6 meters in 10 seconds, how much work does the person do on the box?a. 180 joules b. 200 joules c. 1800 joules d. 18000 joules
15.) A 10-kilogram ball is fired with a velocity of 500 meters per second from a 1,000 kilogram cannon. What is the recoil velocity of the cannon?a. 5 m/sec b. 2 m/sec c. 10 m/sec d. 500 m/sec
16.) A 120 kg lineman moving right at 2 m/s tackles an 80 kg football fullback moving left at 8 m/s. After the collision, both players move left at 2 m/s. What is the momentum of the players after the collision?
a. momentum of lineman= 240 kg m/s and momentum of fullback =160 kg m/s
b. momentum of lineman=240 kg m/s and momentum of fullback= 640 kg m/s
c. momentum of lineman= 720 kg m/s and momentum of fullback= 320 kg m/s
d. momentum of lineman= 400 kg/m/s and momentum of fullback= 400 kg m/s
17.) A baseball player throws a ball horizontally. Which statement best describes the ball's motion after it is thrown? (neglect the effect of friction)a. It's vertical speed remains the same, and its horizontal speed increases
b. It's vertical speed remains the same, and its horizontal speed remains the same
c. It's vertical speed increases, and its horizontal speed increases
d. It's vertical speed increases, and its horizontal speed remains the same
18.) An object falls freely near the Earth's surface. Which best represents the relationship between the object's kinetic energy and its time of fall?a. Kinetic energy increases at a constant rate
b. Kinetic energy decreases at a constant rate.
c. Kinetic energy decreases by time squared
d. Kinetic energy increases by time squared