Kinematics
What does the slope of a position time graph represent?
Velocity
A 10 kg object accelerates at 2 m/s². What is the net force?
20 newtons
When is mechanical energy conserved?
When there are only conservative forces acting on the system
A 2 kg object moving at 4 m/s hits a wall and stops. What is the change in momentum?
-8
What is torque the rotational equivalent of?
Force
under what circumstances can you use the equation x=vot+1/2at^2?
When the acceleration is constant
Why does a passenger lurch forward when a car suddenly stops?
Inertia
A constant force delivers an average power of 10 W to a 10kg box. The average speed of the box is 2 m/s and the force is exerted in the direction of motion. What is the magnitude of the force?
5N
Why does a gun recoil when fired?
Because the gun must go backward for the bullet to go forward
Why is it easier to open a door from the handle than near the hinge?
Because torque depends on the distance from the axis of rotation
An object moves with constant acceleration. How can you determine displacement from a velocity–time graph?
Calcuating the area under the curve
A box of mass m sits on a frictionless surface. Two forces are applied to it: a 12 N force to the right and a 4 N force to the left. If the box accelerates at 2 m/s², what is the mass of the box?
4kg
the negative slope of what graph is equal to the force?
Potential energy vs position graph
Why is it safer to land on a soft surface than a hard one in terms of impulse?
Because it increases the impact time which decreases the average impact force
if you can do 20 pushups you can get the points
A ball is thrown upward and caught at the same height. Compare its speed at launch and just before being caught.
It is the same
A planet of mass M and radius R has uniform density throughout its volume. Derive an expression for the gravitational field of the planet at a point a distance R/4 below the surface of the planet.
3GM/4R^2
A block of mass m = 0.2 kg on a frictionless ramp is pressed against a spring with spring constant k = 800 N/m, compressing it a distance Δx = 0.1 m. The block is released and travels up the ramp. What is the height of the block above its initial height when it has a speed v = 5.0 m/s?
.77m
A toy car of mass m = 4 kg accelerates across a surface in a straight line. The kinetic energy of the car increases from 8 J to 18 J while accelerating. What is the change in momentum of the car?
4kg
A disk of radius R moves with negligible friction along a horizontal surface with a translational velocity v as it rotates with an angular velocity ω. Which of the following statements must be true regarding the angular velocity of the disk?
(A) ω = v/R
(B) ω < v/R
(C) ω > v/R
(D) A relationship cannot be determined for ω in terms of v and R.
D!!!
A projectile is launched vertically with an initial speed of v₀ and reaches a maximum height of h. A second, identical projectile is then launched with the same initial speed at an angle of 30° above horizontal. What maximum height does the second projectile reach?
Two satellites are orbiting Earth in circular orbits. Satellite A has a mass m₀, orbital period T₀, and orbital radius R_A. Satellite B has a mass 2m₀, orbital period 2T₀, and orbital radius R_B. What is the ratio R_B/R_A?
4^1/3
Sphere A, with mass M_A, is dropped from a cliff. Once Sphere A has fallen distance h_A, it has a kinetic energy K_A. Sphere B, with mass 3M_A, is dropped from the same cliff. How much kinetic energy does Sphere B have once it has fallen a distance of h_A/4?
K_b=3/4K_a
A box of mass m slides across a horizontal surface with an initial kinetic energy K. The coefficient of kinetic friction between the box and the surface is μ. Derive an expression for the time the box will slide before coming to rest.
sqrt(2k)/mg^2*mew^2
A disk of radius R rotates about an axis passing through its center and perpendicular to the plane of the disk. The initial angular speed is ωᵢ and the disk is given a constant negative angular acceleration −α₀. Derive an expression for the magnitude of the net linear acceleration of a point at the edge of the disk in terms of R, ωᵢ, α₀, and t.
R*sqrt(a0^2+(w_i-a_0t)^4)