Net Force or No Net Force?
A book is resting on a desk and remains motionless.
What is the normal force balancing gravity, resulting in zero net force?
An object remains at rest unless acted on by a net force.
What is Newton’s First Law?
This law explains why an object accelerates when the net force is not zero.
What is Newton’s Second Law?
This diagram shows all forces acting on a single object.
What is a free body diagram?
True or false: An object must have a force acting on it to keep moving.
What is false?
A car moves at constant speed on a straight, level road.
What is zero acceleration because the net force is zero?
An object continues moving at constant velocity when the net force is zero.
What is Newton’s First Law?
A 2 kg object experiences a net force of 10 N.
What is an acceleration of 5 m/s²?
A box rests on a table. Name two forces acting on the box.
What are gravity and normal force?
Motion stops because this force creates a net force opposite motion.
What is friction?
A box is pushed to the right with 40 N while friction acts to the left with 40 N.
What is balanced forces producing a net force of 0 N?
Newton’s First Law is the case when this quantity equals zero.
What is net force?
Two objects experience the same net force, but one accelerates less.
What is the object with greater mass?
A box is pushed across a rough floor at constant speed.
What are applied force and friction balancing each other?
Two equal and opposite forces act on an object and it does not accelerate.
What is zero net force?
A hockey puck slides across ice after being struck and gradually slows down.
What is a nonzero net force caused by friction?
A student says, “The object is moving, so there must be a force pushing it forward.”
What is an incorrect statement explained by Newton’s First Law?
box is pushed to the right with 50 N and friction acts with 20 N to the left.
What is a 30 N net force to the right?
Which force is often missing when students draw a free body diagram of an object at rest on a surface?
What is the normal force?
A student confuses force with net force. Correct them using one sentence.
What is acceleration depends on net force, not individual forces?
An object is moving, but its velocity is not changing.
What is constant velocity indicating zero net force and zero acceleration?
Explain why Newton’s First Law can be considered a special case of Newton’s Second Law.
What is when net force is zero, acceleration is zero, so velocity is constant?
Explain why doubling the mass while keeping net force constant halves the acceleration.
What is because acceleration is inversely proportional to mass in a=Fnet/m
Why should Newton’s Third Law force pairs never appear on the same free body diagram?
What is because they act on different objects?
Explain why an object can move while the net force acting on it is zero.
What is because zero net force means zero acceleration, not zero velocity?