Newton Second Lab Questions.
You will be quizzed on these questions the week after the corresponding lab has been
performed. Please show all your work for credit. You will not receive credit for just writing the
answer without showing all the steps and equations. Untidy work will not be graded.
1. An 800 Kg elevator is initially moving downward at 10 m/sec; it slows to a stop with a
constant acceleration in a distance of 25 meters. Find:
a. The value of the acceleration. Ans: 2 m/sec2 upwards
b. The value of the tension T in the supporting cable while the elevator is being
brought to rest. Ans: 9448 N
2. You push a 1.00 Kg food tray through the cafeteria line with a constant horizontal force
of 9.0 Newton (see graph below). The tray pushes on a 0.50 Kg carton of milk. The tray
and carton slide on a horizontal surface so greasy that friction can be neglected. Find:
a. The acceleration of the tray and carton. Ans: 6 m/sec2
b. The horizontal force that the carton exerts on the tray.
Ans: 3 N opposite to the 9 N force direction