Force and Newton's laws
The inertia of an object is directly proportional to its ____
What is mass?
The force acting perpendicular to the incline's surface is called the ____ force.
What is the normal force?
What does y-y0 represent?
What is height or vertical displacement?
What is the single letter symbol for momentum?
What is p?
Instead of being a vector, temperature is a ____.
What is a scalar?
What is the formula for Newton's second law?
What is Net force = (mass)(acceleration)
True or false. The greater the incline angle, the lower the sliding force.
What is false?
Sliding force=mgsinθ
The closer θ approaches 90 degrees the greater the value of sinθ
What can we assume about the initial velocity of an object which is dropped straight down?
What is 0 initial velocity?
What is the formula for momentum?
What is p= (mass)(velocity)
A vector has both ____ and _____.
What is magnitude and direction?
An object has a mass of 250 grams. Calculate the force due to gravity.
What is 2.45 N?
Mass in kg: 250 g×(1 kg/1000 g)=0.25 kg
Force due to gravity:0.25 kg×9.8 m/s2 =2.45 N
If the incline angle is 30 degrees, then find the sliding force which acts on a 2 kg object. Remember the side lengths of a 30-60-90 triangle are x, sqrt3×(x), 2x
What is 9.8 N?
Sliding force=mgsin30
= 2 kg(9.8 m/s2)0.5 = 9.8 N
An object experiences free fall for 2 seconds. How far in meters did the object fall?
What is 19.6 m?
(y-y0)=vy0t + 1/2at2
. =0×t + 1/2(9.8 m/s2)(2 s)2 = 19.6 m
What is the difference between an elastic and inelastic collision?
During an elastic collision, the objects separate from each other after the collision. During an inelastic collision, the objects stick together after the collision.
The slope of a position-time graph represents the _____.
What is velocity?
If the pulling force acting on a 2.0 kg object is 15 N, and the frictional force is 5 N, find the object's acceleration.
What is 5.0 m/s2?
Net force=15 N - 5 N = 10 N
10N = (2.0 kg)a
Find the normal force acting on a 1 kg object on a 45 degree incline?
What is 6.9 N?
Normal force=mgcosθ=1 kg(9.8 m/s2)cos30
Since cos30=0.866, normal force = 6.9 N
An object is thrown straight up with an initial velocity of 12 m/s. What is the maximum height reached by the object?
What is 7.35 m?
v2=v02+2a(y-y0)
02 = (12 m/s)2+2(-9.8 m/s2)(y-y0)
Solve for y-y0
What is the formula which shows the relationship between kinetic energy and momentum?
What is
Kinetic energy=p2/2m
For an object experiencing free fall, describe the acceleration-time graph slope if air resistance is ignored.
What is 0?
The acceleration-time graph yielda a horizontal line since the acceleration value remains constant at 9.8 m/s2.
Explain why the terminal velocity of a falling object is constant (remember we are not ignoring air resistance).
The net force (force due to gravity-air resistance) is 0, meaning that the object experiences zero acceleration, meaning that the velocity is constant.
v=v0+at, so if a =0, v=v0
The coefficient of kinetic friction μk = 0.2 between the object and a 1 kg mass. Find the frictional force of the sliding object.
What is 2.45 N?
Frictional force=μkmgcosθ when the object is already moving
=0.2(1 kg)(9.8 m/s2)cos60, since cos60=0.5
Frictional force = 2.45 N
If you were to draw a position-time graph for an object experiencing free fall, describe the curve for the position-time graph.
What is a parabolic curve?
y-y0 = vy0t+1/2at2
Since vy0=0, displacement (change in position) is directly proportional to t2.
Which of Newton's force laws was used to derive the Conservation of Momentum?
What is Newton's third law?
In which quadrant does the velocity-time graph appear for an object moving backwards and faster appear?
What is quadrant 4?