Motion Equations
& Graphs
& Graphs
State the kinematic equation that does not include time.
vf2 = vi2 + 2aΔx
The action force : Mattea pushes the suitcase forwards across the floor.
State the reaction force.
The suitcase pushes Mattea backwards.
Two objects are launched horizontally from a cliff that is 100 m high. One has a mass of 2 kg, the other 4 kg. The 2 kg mass is launched at 2 m/s while the 4 kg mass is launched at 4 m/s. The 2 kg mass hits the ground at time t2. In terms of t2, state when the 4 kg mass hits the ground.
(A) t2 (B) 2*t2 (C) 0.5*t2 (D) 4*t2
(A) t2
A 5 kg sign is supported by two symmetrical ropes, each at an angle of 50 degrees to the horizontal. The angle to the horizontal then increases to 60 degrees. As a result, the tension in the ropes will
(A) increase (B) decrease (C) remain the same
B (decrease)
A block of mass m is placed on a ramp at an angle theta. What is the expression for the parallel component of gravity on the block?
mgsin(theta)
A velocity vs time graph has a horizontal line at 3 m/s over the first four seconds of motion. State the displacement of the object.
12 m
An applied force of 40 N is pulling a mass of 2 kg along the floor which has a coefficient of friction of 0.5. What is the acceleration of the mass?
15 m/s2
An object is launched horizontally off a cliff with a speed of v0. Which of the following claims is correct about the projectile?
(A) Both its horizontal and vertical velocities increase at a regular rate.
(B) Both its horizontal and vertical accelerations increase at a regular rate
(C) Its horizontal velocity remains constant but its vertical velocity increases
(D) Its horizonal acceleration remains a constant non-zero value and its vertical acceleration increases at a regular rate
One Atwood machine contains two masses, a 1 kg and a 2 kg mass. A second Atwood machine contains two masses, a 2 kg and a 3 kg mass. Which system will have the greater acceleration?
(A) the 1 and 2 kg system
(B) the 2 and 4 kg system
(C) they will be the same
(D) it depends on the size of the pulley
(C) they will be the same
A 2 kg block is being pulled up a 20 degree frictionless ramp at constant speed. State the applied force on the block.
6.8 N
A ball has been thrown up vertically in the air, and then returns to the hand that threw it. Sketch two velocity vs time graphs for this motion, one in which the upwards direction is positive and one in which the downwards direction is positive.
1st graph : diagonal line downwards from positive quadrant to negative. Equal areas in each quadrant.2nd graph : diagonal line upwards from negative quadrant to positive. Equal areas in each quadrant.
A block of mass m at rest on a table is being pulled with force F. State a simplified expression for the force F on the block in terms of basic variables (m, x, v, a, etc) and constants.
F = Ffr = µ mg
A projectile launched at 2 m/s lands 12 m away from the base of a cliff. From what height was it launched?
t = 6 seconds
Δ y = 180 m
A package is being supported by two ropes. One rope has a tension of 100 N at an angle of 30 degrees to the horizontal. The other rope has a tension of 173 N at an angle of 60 degrees to the horizontal. What is the mass of the package?
20 kg
An object of mass <m> moves with acceleration <a> down an incline that makes an angle <θ> with the horizontal. The coefficient of friction between block and incline is <µ>. Write a simplified expression for the acceleration of the mass in terms of basic variables and constants.
a = gsinθ - µcosθ
An object accelerates upwards for 2 seconds at a rate of 3m/s2. Then it moves with constant velocity for 10 seconds. Then it slows down for 4 seconds at a rate of -1 m/s2. What is the total displacement of the object?
74m
A soccer player has given a ball a kick. Now the ball is slowing as it rolls across the grass at a rate of 4 m/s2. State the coefficient of friction between ball and grass.
0.4
A projectile launched horizontally with a velocity of 3 m/s lands after 0.4 seconds. What is its resultant velocity and at what angle does it land?
5 m/s at 317 degrees
A mass M is on a table, attached by a string to a frictionless pulley and a weight W hanging. State the friction on the table if the system is in equilibrium.
(A) M (B) Mg (C) Ffr (D) W
(D) W
A 3 kg block is sliding down a 10 m long ramp with a coefficient of friction of 0.3. The ramp is at an angle of 35 degrees with the horizontal. What will be the velocity of the block when it reaches the bottom of the ramp?
3.3 m/s