Weight, Weight, Don't Tell Me!
What is the weight of a 50 kg man in New York where g = 9.802 m/s2?
490 N
What is inertia? What property has the greatest effect on inertia?
Inertia is the tendency of an object to resist a change in its motion. Mass has the greatest effect.
A 450 kg object is orbiting the moon and is attracted to the moon with a force of 850 N. What is the magnitude of the object's acceleration to the nearest m/s2?
1.89 m/s2
What is the net force & acceleration of an object in equilibrium?
Zero
What is the definition of force?
The cause of an acceleration.
A 100 kg crate requires 1000 N to set it into motion. What is the weight of the crate?
980 N
What is the definition of mass? What are its' units?
Mass is a measure of the quantity of matter. Its' units are kg.
Which is less: the force required to cause a stationary object to begin moving or the force necessary to keep it moving at constant speed?
Less: force necesary to keep it moving at constant speed.
Why is a student sitting in a chair in equilibrium?
The weight of the student down & the upward force of the chair on the student are equal in magnitude, but opposite in direction.
Is force a vector or scaler?
Vector
The higher the altitude, the more or less you weigh?
less
What is the definition of weight? What are its' units?
Weight is the magnitude of the force of gravity on an object. Its' units are N.
A 20 kg box requires a force of 111 N to keep it moving at a constant velocity. What is the magnitude of the friction force and what is the coefficient of kinetic friction?
111 N; 0.57
If a moving car has a horizontal net force equal to zero, what is the motion of the car?
Moving at a constant speed, has zero acceleration.
A teacher is pushing a 150 kg cart down a hall and applies a horizontal force of 130N. What is the definition of normal force? What is the normal force on the cart?
The upward, supporting force on the cart; 1470 N
The higher the latitude, the more or less you weigh?
more
What is the definition of kinetic & static friction? Which is greater?
static refers to friction between two objects at rest, kinetic refers to two objects in motion. Static is the greater.
A 50 kg crate requires a force of 300 N to set it in motion. What is the magnitude of the frictional force & what is the coefficient of static friction?
300 N; 0.61
A woman pushes a grocery cart with a force of 25 N? What is the force of the grocery cart on the woman? This is an example of which of Newton's Laws of Motion?
25 N; 3rd Law of Motion - action/reaction
A 3 kg block on a frictionless horizontal surface has two forces acting on it: 5 N to the right and 3 N to the left; what is the net force acting on the block and what is the acceleration of the block?
2N to the right; 0.67 m/s2
The normal force acting on an object sliding on a horizontal table at a constant speed is 300 N. What is the weight of the object?
300 N
Draw the distance vs time graph & velocity vs. time graph for an object where the net force is 0?
At rest: position doesn't change, v and a =0
At constant v: position changes at constant rate, v is constant and a =0
If it takes 3 N to drag a 9 N shoe at constant speed across a carpet, what is the coefficient of friction between the shoe and the carpet?
0.33
An object moving at constant velocity is...
in equilibrium, it is not accelerating, the forces on the object are balanced, and the net force is zero.
A bicyclist riding on a path hits a tree stump. The 55 kg rider is thrown over the handlebars at 10 m/s into a creek bed. The rider is brought to rest in 0.40 sec. What is the magnitude of the average force exerted on the cyclist by the creek bed?
1375 N