Forces
What is Newton's second law?
The sum of forces equals mass time acceleration
What are the two types of friction?
Kinetic and Static
What is the formula for Kinetic, Potential, and spring potential energy?
KE=1/2mv^2
PE=mgh
PEs= 1/2kx2
Forces are acting on a wheelbarrow wheel so the wheel rotates with a constant angular velocity. The time it takes for the wheel to rotate through one revolution is:
A. ΞΈ
B. T
C.Ξ±
D.
B
What is the conservation of momentum?
That the momentum of a system is conserved if there is no net force acting on the system.
Draw a free body diagram for a pumpkin on a wagon that is tilted 25deg above the horizontal.
Normal force perpendicular to the wagon.
Gravity straight down.
Which directions do static and kinetic friction act
Kinetic- opposing motion
Static- in the direction of intended motion
A bag of candy with a mass of 2Kg is taken from the ground to the height of 10m. Find the potential energy of the candy bag.
196Nm
The centripetal force on an object is:
A. the combination of forces necessary to cause an object to move in uniform circular motion.
B. centrifugal force.
C. the force that causes uniform circular motion.
D. the force that is created when moving in circular motion.
A
What is the difference between elastic and inelastic collisions?
Elastic collisions- KE is conserved
Inelastic collisions- KE is not conserved
If you apply 15 π of force to a pumpkin and cause it to accelerate at 3 m/s2, what is the objectβs mass?
5kg
A 5.00kg pumpkin is being pulled at constant speed up a 30o wheelbarrow by a force of 45.0N parallel to the incline. Determine the coefficient of kinetic friction between the pumpkin and the wheelbarrow.
0.483
Find the kinetic energy of the clown's juggling ball just before hitting the ground. Assume that initially, the ball was at a height of 7.5m, and its mass was 1.5Kg.
110Nm
A hayride wagon wheel rolls for two meters. If the wheel is one meter wide, what was the angle through which the wheel turned?
π = s/=2/(1/2)= 4 rad
A 1300 kg pumpkin is rolling down a hill at 80 m/s while a 15,000 kg wheelbarrow is traveling at 20 m/s. Which has the greater momentum?
Car: 104,000 kg*m/s,;
Truck: 300,000 kg*m/s
You are at Stults farm picking pumpkins with your roommates. You grab a 10 kg wagon and pull it across the fields with a force of 25 N. The rough dirt exerts a force on the wagon that is equal to 10 N in the direction opposite the motion of the wagon. What is the acceleration of the wagon?
1.5 m/s^2
A 15.0 kg box is being pulled along level ground by a 75.0 N force that is directed at an angle of 20o above the horizontal. The coefficient of kinetic friction is 0.330. What is the acceleration of the box?
2.03 m/s2
Two ghost decorations are kept at different heights, first ghost is at 5m and second ghost is placed at 15m. Which ghost has more Potential energy if the first ghost is 5 times heavier than the second?
Ghost 1: PE=245N
Ghost 2: PE=147N
Two children are riding on a merry-go-round at the state fair and are sitting 2 meters apart from one another radially. If the ride is moving with an angular velocity of 10 πππ/π and the distance between the center of the ride and the child closest to the center is 7 π, what is the difference in tangential velocity between the two children?
π£ = π Ο
v1=r1 Ο= 7*10= 70
v2=r2 Ο= (r1+d)Ο=9*10=90
v1-v2=70-90=20
A 0.375 kg rubber ball that is traveling horizontally to the right at 10 m/s hits a wall and bounces back at 6 m/s to the left. What is the total impulse exerted by the wall on the ball? Take the positive direction as to the right.
πΉΞπ‘ = Ξπ = πΞπ£ = π π£π β π£π = 0.375 β6 β 10 = β6.0 π β π OR 6.0 N*s to the left
You are tossing a bat stuffed animal directly up into the air. Before the bat leaves your hand, you are exerting a force directed against the force of gravity. If you apply a net force of 10 π to a 1 ππ bat, what is the normal force acting on the ball?
πΉπ = π + πΉ = 9.8 + 10 = 19.8N
A child is being pulled down a slide in a haunted house by a horizontal rope. Determine an expression for the coefficient of kinetic friction, ππ, if the child is to move down the slide at constant velocity. Give your answer as a single equation in terms of the childβs mass π, the acceleration due to gravity π, the tension in the rope π, and the angle of inclination of the slide π.
ππ = (π cos π + π sin π)/πΉπ = (π cos π + ππ sin π)/ (ππ cos π β π sinπ)
You are attending fright fest at six flags over GA and are going on a roller coaster. The whole cart weighs 100kg and you are sitting on top of a 50m hill. You then slide down to a 50m flat section with a coefficient of kinetic friction ΞΌk= 0.20. The ride continues up the frictionless ramp with an angle of ΞΈ = 45.0Β° before coming to a complete stop. What is that height H2 that the ride reaches on the ramp?
40m
Starting from rest, a disk rotates about its central axis with constant angular acceleration. In 5.0 π , it rotates 25 πππ. During that time, what are the magnitudes of a) the angular acceleration and b) the angular velocity after 5.0 π ?
Ξπ = π0π‘+ 1/2 πΌt2 = 1/2 πΌt2 β πΌ = (2Ξπ)/t2 = 2(25)/ (5)2 = 2 πππ/s2
b) πf2 = π02+ 2πΌΞπ = 2πΌΞπ β ππ = β2πΌΞπ = β(2)(2)(25) = 10 πππ/s
A constant horizontal force of 2.29N is applied to a 1.82kg scarecrow initially at rest on a frictionless surface. How much work is done on the block in the first 1.35s after the force is applied?
πΉΞπ‘ = Ξπ = πΞπ£ = π(π£π β π£0) β π£π = πΉΞπ‘ π β π = ΞπΎ = πΎπ β πΎ0= 1/2 ππ£f2 = 1/2( πΉΞπ‘ π ) 2 = (πΉΞπ‘) 2 2π = 2.62565J