Equations
The equation for net force derived from Newton's 2nd Law
Fnet=ma
Equation for gravitational force on/near the earth's surface
Fg = mg
Equation for spring force
Fs = kx
Calculate the kinetic energy of a 10kg object moving at 5m/s
125J
Calculate the power required to do 50J of work in 10 seconds.
5W
Equation for gravitational potential energy
GPE = mgh
Kinematic equation that does not include displacement
vf = vi + at
Equation for kinetic energy
KE = (1/2)mv^2
Calculate the total mechanical energy of a 5kg object moving at 2m/s at the top of a 4m tall hill.
206.2J
A 20kg object moving at 8m/s slows to a velocity of 2m/s. Calculate the total work done on the object.
-600J
Equation for total mechanical energy
E = KE + PE
Equation for spring potential energy
SPE = (1/2)kx^2
Equation for net force based on its definition
Fnet = F1 + F2 + F3 + ...
How do you tell the difference between an open and a closed system?
Open systems will have an external, unbalanced force doing work on them.
A 70N force is applied to an object at a 25 degree angle causing the object to move 5m. Calculate the work done by this force.
317.21J
Fg = G (m1m2)/r^2
Equation for kinetic friction force
Ff,k = uk FN
Kinematic equation that does not include acceleration
x = (vi + vf)/2 * t
A cart starts at rest at the top of a 7m tall hill. It then rolls to the bottom of the hill. Calculate the final velocity of the cart assuming no energy is lost due to friction.
11.72m/s
A 4kg block is pushed 10m to the right across a rough level surface by a 90N applied force. The coefficient of friction between the block and surface is 0.3. Calculate the total work done on the block.
782.28J
Work equation
W = Fxcos(theta)
Kinematic equation that does not include time
vf^2 = vi^2 + 2ax
Kinematic equation that does not include final velocity
x = vit + (1/2)at^2
A spring with a spring constant of 600N/m is compressed 0.7m. It decompresses causing a cart sitting against it to accelerate. Calculate the work done on the cart by the spring.
147J
A 750N force pushes a block 100m to the right in 30 seconds. Calculate power.
2500W