Author Question: A crane drops a 0.40-kg steel ball onto a steel plate. The ball's speeds just before impact and ... (Read 159 times)

yoroshambo · **on:** Jul 28, 2018

A crane drops a 0.40-kg steel ball onto a steel plate. The ball's speeds just before impact and after are 4.5 m/s and 4.2 m/s, respectively. If the ball is in contact with the plate for 0.030 s, what is the magnitude of the average force that the ball exerts on the plate during impact?
a. 87 N
c. 3.0 N
b. 116 N
d. 3.5 N

Question 2

An electron with a speed of 2.0 106 m/s moves into a uniform electric field of 325 N/C that is parallel to the electron's motion. How long does it take to bring the electron to rest? (me = 9.11 10-31 kg, e = 1.6 10-19 C)
a. 3.5 10-8 s
c. 2.3 10-8 s
b. 2.3 10-6 s
d. 1.2 10-7 s