4. Standard equation
| Fnet | = | ma |
| (N) | (Kg)(m/s2) |
Newton - force needed to give a 1 kg of mass an acceleration of 1 m/s2
Derived unit - A unit that comes from the combination of other units
N = Kgm/s2
Fundamental unit - (opposite) m, s, Kg
Force Questions
Ex 1) What is the force necessary to give a 3.0 kg mass, initially at rest, an acceleration of 5.0 m/s2?
Ex 1) What is the force necessary to give a 3.0 kg mass, initially at rest, an acceleration of 5.0 m/s2?
F = ma
(3.0 kg)(5.0 m/s2)
= 15 N
Ex 2) A force of 30. nt accelerates an object by 15. m/s2.
Find the objects mass.
Ex 2) A force of 30. nt accelerates an object by 15. m/s2.
Find the objects mass.
F = ma
30. N = m (15. m/s2)
m = 2.0 kg
Ex 3) An unbalanced force of 100 nt acts on a 50kg mass for 5 seconds.
Find the acceleration of the mass
Ex 3) An unbalanced force of 100. nt acts on a 50. kg mass for 5.0 seconds.
Find the acceleration of the mass
Fnet = ma
100. nt = (50. kg) a
a = 2.0 m/s2
Ex 4) A 10. kg cart moving with a
velocity of 2.0 m/s is brought to a stop in 2.0 sec. Find magnitude
of the average force used to stop cart.
Ex 4) A
10 kg
cart moving with a velocity of 2m/s
is brought to a stop
in 2 sec. Find
magnitude of the average force used to stop cart.
m = 10. kg
t = 2.0 sec
Vi = 2.0 m/s
Vf = 0 m/s (stop)
F = ?
F = ma
a = ?
| a | = | Vf - Vi | = | 0 - 2.0 m/s |
| t | 2.0 sec |
a = -1.0 m/s2
Fnet = ma
=(10. kg)(-1 m/s2)
= -10. N
Ex 5) The object below has a mass of 5 kg. Find its acceleration.
Fnet = ma
40 N East = (5 kg)a
a = 8 m/s2 East
Ex 6) The block below has an acceleration of 22. m/s2.
What is the mass of the block?
5N2 + 10N2 = R2
Fnet = ma
Fnet = 11.2 N = m(22 m/s2)
m = .50 kg