chapter 3 dynamic motion and chapter 5 work energy power Flashcards
1
Q
Newton’s second law of motion
A
net force = mass x acceleration
F = ma
2
Q
Newton’s third law of motion
A
when 2 body interact
the force they exert on each other are equal in magnitude and opposite direction
3
Q
weight of an object
A
W = mg
4
Q
work done
A
Work=Fs
or cos S to find the vector direction
unit is joule
5
Q
gravitational potential energy
and
kinetic energy
A
Ep = mgh
Ek = 1/2 mv^2
6
Q
energy efficiency
A
useful outputE
efficiency=———————–x 100
total input E
7
Q
power at the rate of work done ( energy is transferred)
A
P=W/t
or
P=Fv
unit is watt or j/s
8
Q
Newton’s first law of motion
A
•An object will remain at rest unless it’s acted by an external force
9
Q
work done by force F
A
1/2 x m x v^2
10
Q
Energy changes
k.e - g.p.e
A
gain in k.e = decrease in g.p.e
