Conceptual Ideas
Application of Equations
Inclines
Tension
What's My Motion?
100
What law explains why you experience recoil when shooting a gun?
Newton's Third Law.
100
A 1000g apple rests on Mr. Lee's desk. What is the weight of the apple? (use g = 9.81)
9.81 N
100
What is the equation for calculating the force due to gravitational force parallel to an incline set at an angle θ from the horizontal?
F = mgsinθ
Remember: For the force due to gravitational force perpendicular to an incline, F = mgcosθ
100
One end of a rope is connected to a block of mass 5kg. The other end of the rope is connected to the ceiling. What is the tension in the rope?
50 N
100
A box is pushed with a force of 8N and has a frictional force of 4N. The box has a weight of 20N. What is its acceleration?
2ms-2
200
An object in free fall is only affected by the force of ___.
gravity
200
A 20kg box on a rough surface is pushed with a horizontal force of 50 N. If the box doesn't move, what is the force due to static friction
50 N
Remember: Static friction will equal the applied force until it exceeds the value of μsFN, where it will begin moving.
200
A 30kg block is sliding down a 30° incline. The coefficient of static friction is 0.35 and the coefficient of dynamic friction is 0.2. Determine the frictional force acting against the motion of the block.
52 N
200
If the force (F) is pulling the blocks with a force of 30N, what is the tension in the rope connecting the two blocks?
20 N
200
3.46ms-2
300
In a spring, what direction does elastic force move in relation to the direction of the spring's displacement?
In the opposite direction of displacement.
300
A spring with a spring constant 10 N/m is stretched with a displacement of x. The resulting elastic force is 35 N. What is the elastic force of the spring if the displacement is doubled?
70 N
300
A 10.0 kg block is placed on a 20° incline with a coefficient of kinetic friction of 0.3. What is the acceleration of the block as it moves down the incline?
0.6 m/s2
300
Create an equation for T2 in terms of M1, T1, and physical constants
T2 = T1 - M1g
300
A rock falls out of an airplane. The rock has a mass of 5kg and experiences a drag force of 10N. What is its acceleration?
8ms-2
400
What, if any, are the units for the following?
#1 Any force (F)
#2 Spring constant (k)
#3 Coefficient of friction (μ)
1.) N or kgm/s2
2.) N/m
3.) No units
400
A 60kg man is going down in an elevator at a rate of 5 m/s2. What is the normal force acting on the man?
300 N
400
A 15kg block is placed on a 35° incline. What is the minimum coefficient of static friction required to prevent the block from sliding?
0.7
400
Create an equation for T2 in terms of M, θ, and physical constants.
T2 = Mgcot(θ)
400
There is no friction. What is the acceleration of the box?
3.42 ms-2
500
In an ideal pulley system, what two components will be constant across the system?
Tension and acceleration.
Remember: Since the bodies will be connected, they will have the same magnitude of acceleration.
500
A block of mass M is sliding down a rough incline with a dynamic coefficient of friction μk at an incline x° from the horizontal. What are the equations for:
#1 The net force acting perpendicular to the incline.
#2 The net force acting parallel to the incline.
Have your equations in terms of M, x, and g.
1.) Mgcosx
2.) Mgsinx - μkMgcosx
500
A 7.0 kg block is at rest on a 40° incline, and a rope pulls it up the incline. If the coefficient of kinetic friction is 0.15, what is the tension in the rope?
52 N
500
Find the tension in each rope:
69.3 N
500
2.31ms-2