Download Print Newton`s Laws problem set #1

Newton’s laws problem Set #1
1) A 2.6 kg book is dropped from a height of 1.5m
a. What is its acceleration?
b. What is its weight in newtons?
c. What is its speed just before hitting the ground?
2) What net external force is required to give a 25 kg suitcase an acceleration of
2.2m/s/s to the right? Draw a Free Body diagram of the suitcase.
3) You pull on the tail of a 200kg baby elephant with a force of 500N.
a. If the frictional force is 260N, what is the net force.?
b. What is the elephant’s acceleration?
4) A boat moves through the water with two forces acting on it. One is a 2100N
forward push by the motor and the other is an 1800N resistive force due to the
water.
a. What is the acceleration of the 1200kg boat?
b. If it starts from rest, how far will it move in 10 sec?
5) A 75 kg person escapes from a burning building by jumping from a window 25m
above a catching net. Assuming that air resistance exerts a 95N force on the
person during the fall, determine the person’s velocity just before hitting the net.
6) You pull an iguana across the table by its tail at a constant speed with a force of
12N. If the iguana has a mass of 3 kg, what is the coefficient of friction?
7) A car is traveling at 20m/s on a flat highway
a. If the coefficient of friction on a rainy day is 0.10, what is the minimum
distance needed for the car to stop?
8) A girl is skating along at 5m/s on frictionless ice when she hits a rough patch. If
the coefficient of friction between the skates and ice is 0.3 and the girl weighs
500N, how far does she travel before she stops?
Answers
1) a = 10m/s/s, weight = 26N, speed = 5.5m/s 2) 55N
3) net force=240N, a = 1.2m/s/s
4) a=0.25 m/s/s, d = 12.5m
5) v = 24m/s 6) coefficient = 0.40
7) d = 200m
8) d = 4.2m