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Final Jeopardy Question Final Jeopardy Question Energy Gravity Forces Mix
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Final Jeopardy Question
Energy
500
100200300400
Gravity
500400300200100
Forces
500400300200100
Mix
100200300400500
A 10kg ball is dropped from a height of 5m. It lands on a spring (k=100N/m). 175 J are lost as friction in the fall. When the ball is moving 5m/s, how far is the spring compressed?
Back
GPE before hand = 10kg*10m/s/s*5m = 500JTE = 500J – 175J = 325J KE after = ½ 10kg (5m/s)2 = 125JSPE after = 325J – 125J = 200J200J = ½ * 100N/m (x) 2
X2 = 200J / 50N/m = 4m2
X = 2m
A 20kg ball is moving 20m/s when it rolls up a hill. How far up the hill does the ball make it?
Back
KE = ½ 20kg * (20m/s) 2 = 4000JGPE after = 4000J = 20kg * 10m/s/s * hh= 4000J/(20kg*10m/s/s)h = 4000J/200kgm/s/sh= 20m
A 5kg ball is falling 10m/s at a height of 12 m and lands on a spring (k=150N/m). How far does the spring compress?
Back
KE = ½ * 5kg * (10m/s) 2 = 250JGPE = 5kg * 10m/s/s * 12m = 600JTotal energy = 850J
SPE = 850J = ½ 150N/m (x) 2
X2 = 850J / 75N/m = 11.33 m2X= 3.36m
A 15kg ball is compressed in a spring (k=100N/m) 3m. How high in the air will the ball make it?
Back
SPE = ½ 100N/m (3m) 2 = 450J
GPE = 450J = 15kg * 10m/s/s * h
h = 3m
A 10kg ball is at a height of 50m and moving 10m/s. How much total energy does it have?
Back
TE = KE + GPE = ½ * 10kg * (10m/s) 2 + 10kg * 10m/s/s * 50m
500J + 5000J= 5500J
Back
A scale records 100kg person’s weight on an elevator as being 200N. Which
direction and at what rate is the elevator accelerating?
Fdown = 100kg* 10m/s/s = 1000NFup = 200N
Fnet = 800N downA = Fnet/m = 800N/100kg = 8m/s/s down
A 75kg person is accelerating upwards on an elevator 4m/s/s. What weight would a scale say they weigh?
Back
Fnet = m*a = 75kg * 4m/s/s = 300N upFdown = 75kg*10m/s/s = 750N
Fup = 1050N
Back
A 20kg mass is hanging (not accelerating) from a spring (k=200N/m). How far does the
spring stretch?
Fdown = 20kg*10m/s/s = 200NFup = 200N = 200N/m * x
X = 1m
A mass is stretching a spring (k=175N/m) 2m. What must be its mass?
Back
Fup = 175N/m * 2m = 350NFdown = 350N = 10m/s/s * m
m = 35kg
Draw the FBD for a 10kg mass stretching a spring
Back
You have 4x as much mass as normal, but are 3x as far from the center of the Earth. What happens to the force of gravity
4x as much because of your mass, but 1/9th because of your distanceSo 4/9ths
Back
The acceleration of a 5kg person on Planet Physics is 100m/s/s. What is the weight of a 20kg dog on Physics
Back
Weight = Fg = m * g= 20kg * 100m/s/s = 2000N
Back
Any object on Physics will accelerate at a greater rate
Planet Physics is 3x as big as Earth. Which accelerates at a greater rate, a 30kg mass on Earth, or a 10kg mass on Physics?
An object has a weight of 30N. What is the mass?
Back
30N/10m/s/s = 3kg
A satellite is twice the distance from the center of the Earth. What is it’s acceleration?
10m/s/s /4 = 2.5m/s/s
Back
A 5kg mass is accelerating downwards 5m/s/s while attached to a spring (k=5N/m). How far is the spring
stretched?
Back
Fnet = 5m/s/s * 5kg = 25N down
Fg = 5kg *10m/s/s = 50N downFs = 25N up
25N = 5N/m*xX = 5m
An 5kg object stretches a spring (k=40N/m) 5m. Which way and at what rate does the object accelerate?
Back
Fup = 40N/m * 5m = 200NFdown = 5kg * 10m/s/s = 50NFnet = 150N upa = 150N/5kg = 30m/s/s
A 5kg object stretches a spring 5m. What is the spring constant? How much
SPE does the object have?
Back
K = F/x = 5kg*10m/s/s / 5m = 10N/mSPE = 1/2kx2 = ½ 10N/m * (5m) 2
SPE = 125J
A 5kg object is on top of a 10m hill. At the bottom it is moving 10m/s/s. How much energy was lost as friction?
Back
GPE = 5kg * 10m/s/s * 10m = 500JKE at bottom = ½ 5kg * (10m/s) 2 = 250JEnergy lost = 250J
What does it mean to have a large spring constant?
Back
It takes a large force to stretch the spring
Name and define as many physics terms from this unit as you can
Force, GPE, KE, SPE, Spring Force, Weight, Mass, Acceleration, Net Force, Velocity, Spring Constant, Gravity, Conservation, etc.
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