Forces and Gravity

PHYC 110
Physical Science
Name _______________
Date ________________
Exercise 6: Force and Gravitational Force
Circumference of circle = 2πR
G = 6.67x 10– 11 N–m2/kg2
1 g = 9.8 m/s2
1. A force of 5,000 N is exerted on a 35.0-gram rifle bullet when it is fired. What is its
F = 1,000 N
F = ma
m = 35.0 grams x (1 kg/1000 grams) = 0.035 kg
F = ma
5000 = (0.035) a
a = 143,000 m/s2
2. Four forces act on a 2.0-kg object: 10. N down, 10. N up, 5.0 N left, 10. N right.
a. Will the object move?
Up and down, they are the same, so balanced.
Left and right, not the same, so unbalanced.
Yes, forces are unbalanced in direction, so it will move.
b. If the answer to (a) is “Yes,” what will be its acceleration and in what direction?
Right = + 10 N, left = −5 N
Forces left and right: +10 − 5 = +5, net force is 5 N to the right.
5.0 = 2.0 a
a = 2.5 m/s2
3. A hunter whirls a
a horizontal circle
should he release
target? (b)
stone attached to a string in
above his head. Where
the string to hit the
4. Tyrone and Mia have masses of 84 kg and 59 kg respectively. They sit 1.0 m
apart in the front center of Mr. H's Physics class. For some time, they each have
been sensing a sort of electricity in their growing relationship. And now, six weeks
into their Physics course, they have learned that they are gravitationally attracted to
each other. Determine the magnitude of this force of gravitational attraction.
GmT mM (6.67 x10 11 )(84)(59)
F  3.3x10 7 N