what happens to the acceleration of an object if the force applied to it doubles
the acceleration boubles
what is the net force on a car that moves with 7250 N thrust and experiences 200 N of air resistance and 5000 N of gravity?
7050 N forward
A single force acting on an object is represented in a free-body diagram of the object by the following force vector: ↑. Which of the following force vectors represents a single force acting on the object that will bring the object into equilibrium?
a. ↑
b. →
c. ↓
d. ←
c. ↓
This law describes the need for an unbalanced force in order for an object to undergo an acceleration
What is Newton's Second Law of Motion?
Which of the following will increase the acceleration of an object that is pushed by a force?
a. decreasing the mass of the object
b. increasing the mass of the object
c. increasing the force pushing the object
d. Both (a) and (c)
a and c
Assuming 1 kg = 1,000 g, a 5 kg object has less inertia than an object with a mass of
a. 4 kg. c. 2 kg.
b. 6,000 g. d. 1,500 g.
b. 6,000 g
In an action-reaction pair, the
a.action force is exerted first.
b.action force and the reaction force are equal in magnitude and act in the same direction.
c.action force and the reaction force are contact forces only.
d.action force and the reaction force act on two different objects.
d.action force and the reaction force act on two different objects.
Applying Concepts When a truck pulls a trailer, the trailer and truck accelerate forward even though the action and reaction forces are the same size but are in opposite directions. Why don’t these forces balance each other?
because the action and reaction forces act on different objects
What force is necessary to accelerate a 70 kg object at rate of 4.2 m/s2 to east? Show your work below.
294 N east
Which of the following statements describe an object in equilibrium?
I. The object is at rest.
II. The object is moving at constant velocity.
III. The net external force on the object is zero.
a. I and II
b. I and III
c. II and III
d. I, II, and III
d. I, II, and III
Making Inferences Use Newton’s first law of motion to explain why airbags in cars are important during head-on collisions.
due to inertia of occupants inside a car, the occupants keeps going with the same speed of the car during an accident. No external unbalanced force is to stop them. the airbags and seatbelt exert an unbalanced force in opposite direction to push occupants back.
a tennis ball of mass 0.03 kg hits the ground with 2 newtons. what is the reaction force exerted on the tennis ball. which objects exert the action & reaction forces?
- 2 N
tennis ball exerts the action force
the ground exerts the reaction force
draw a free body diagram of a running soccer ball player.
gravity / normal force
applied force of muscles / air resistance, friction
Explain how action-reaction pairs keep a book sitting on a table in equilibrium.
the gravity pulls the book down but the table exterts a normal force that balances the gravity. the result is zero net force on the book
This law states that forces come in pairs.
what is the third law of motion
Imagine you accidentally bumped your hand against a table, as shown in the image below. Your hand hurts after it happens. Use Newton’s third law of motion to explain what caused your hand to hurt.
my hand exerts a force on the table and at the same time the table exerts the same force on my hand. this reaction force causes my hand hurt
A child tugs on a rope attached to a 0.62-kg toy with a horizontal force of
16.3 N. A puppy pulls the toy in the opposite direction with a force 15.8 N. What is the acceleration of the toy?
0.8 m/s2
how thirld law of motion apllies to the space shuttle?
the action reactio pair of the gas explosion and the push on the space shuttle that lifts it
A truck and a car uniformly accelerate from rest to a velocity of 3.0 m/s in equal time intervals. The truck is ten times as massive as the car. Which of the following statements is correct?
a.The acceleration of the truck is 1/10 that of the car.
b.The truck travels 1/10 the distance of the car.
c.The force on the truck is 10 times the force on the car.
d.all of the above
c.The force on the truck is 10 times the force on the car.