Forces
What are the units for forces
Newtons
A boy throws a 1 kg rock with a force of 5 N. Find acceleration when he lets go of the rock.
5 m/s^2
Objects with more mass require ______ force in order to experience the same rate of acceleration
more
A boy throws a 1 kg rock with a force of 5 N. Calculate the rate of acceleration
0.2 m/s^2
Which would hit the ground first if dropped from a ladder? object with small mass or large mass?
They would hit the ground at the same time
Unbalanced forces result in _________
change in motion
The net force pushing a 15 kg wagon results in an acceleration of 2 m/s^2. What is the net force on the wagon?
F= 30 N
If given the same force, objects with _____ mass experience a slower acceleration
more
What is the formula for calculating weight
W = m x g
Which would change on the moon? mass or weight? Why?
weight
weight is mass x gravity
True or False: Objects experiencing balanced forces are at rest
False
What is the amount of force required to accelerate a 20 kg object to 30 m/s^2?
F= 600 N
In order to accelerate at the same rate, objects with _________ mass require less force
less
A net force of 15 N is exerted on an encyclopedia to cause it to accelerate at a rate of 5 m/s2. Determine the mass of the encyclopedia.
m = 3.0 kg
Toy car 1 is pushed with 30 N of force, then the same car is pushed with 50 N of force. Which amount of force will cause the fastest acceleration?
50N
What force opposes gravity
normal force
An object with a mass of 1500 g accelerates for 10.0 m/s^2 when force is applied. What is the magnitude of the force?
F= 15 N
Objects with more mass would experience ________ acceleration if given the same force (compared to a smaller mass)
less
Suppose that a sled is accelerating at a rate of 2 m/s2. If the net force is tripled and the mass is doubled, then what is the new acceleration of the sled?
Answer: 3 m/s/s
The original value of 2 m/s/s must be multiplied by 3 (since a and F are directly proportional) and divided by 2 (since a and m are inversely proportional)
With unbalanced forces, the object will move in the direction that the _______ force is being applied.
larger/stronger
Which would hit the ground first if dropped: Bowling ball or tennis ball?
Neither, they would fall at the same rate of acceleration due to gravity
Calculate the mass of a falling object if it hits the ground with a force of 24 N
2.45 kg
Which variables in this equation have an inverse relationship?
F=ma
Force and Mass
Suppose that a sled is accelerating at a rate of 2 m/s2. If the net force is tripled and the mass is halved, then what is the new acceleration of the sled?
Answer: 12 m/s/s
The original value of 2 m/s/s must be multiplied by 3 (since a and F are directly proportional) and divided by 1/2 (since a and m are inversely proportional)
A cart is being moved by a constant net force. You place a bag of dog food in the cart, and now the mass of the cart has doubled. How has the acceleration changed?
acceleration has halved if mass is doubled