When the index card is quickly pulled away from the glass in a horizontal direction, why does the disk fall straight down into the glass?

A.
equilibrium

B.
static friction

C.
kinetic friction

D.
inertia

9 answers

D. inertia
A student is investigating mass and acceleration. The student applies the same force to two boxes, as shown in the table.


Box Force Applied to Box (newtons) Acceleration (meters/second2)
1 20 5
2 20 2
The student claims that box 1 must have a smaller mass than box 2. Which argument best supports the student's claim?
A.
Heavier objects require less force than lighter objects to accelerate at the same rate.

B.
Heavier objects require greater force than lighter objects to accelerate at the same rate.

C.
Lighter objects require less force than heavier objects to start moving but will accelerate at the same rate.

D.
Lighter objects require greater force than heavier objects to start moving but will accelerate at the same rate.
B.
Heavier objects require greater force than lighter objects to accelerate at the same rate.
A student is investigating the distribution of charges in insulators. The student will place an aluminum metal can on top of a foam cup and touch the side of the foam cup with a negatively charged rod. The set up for the investigation is shown in the diagram.

What will MOST LIKELY happen to the electrons when the rod touches the foam cup?

A.
The electrons will pass to the foam cup but will remain in a localized, positively charged area on the cup where the rod was placed.

B.
The electrons will pass to the foam cup but will remain in a localized, negatively charged area on the cup where the rod was placed.

C.
The electrons will pass from the foam cup to the aluminum can, and both the foam cup and the aluminum can will become positively charged.

D.
The electrons will pass from the foam cup to the aluminum can, and both the foam cup and the aluminum can will become negatively charged.
C.
The electrons will pass from the foam cup to the aluminum can, and both the foam cup and the aluminum can will become positively charged.
A student is designing an investigation of the distribution of charges in conductors. She will use two conducting spheres mounted on insulating stands in the investigation. The conducting spheres are shown.

image 20dd73ed8cf143748d14ec76f16d7970

The student wants to separate the charges of the spheres as shown.

image 6e01081a67464a9cb75abfdb169f19b8

What should the student do in her investigation to produce these results?

A.
She should place a negatively charged rod near the left sphere.

B.
She should place a positively charged rod near the left sphere.

C.
She should place two negatively charged rods near each sphere.

D.
She should place two positively charged rods near each sphere.
B.
She should place a positively charged rod near the left sphere.
A ball rolls down a grassy hill and eventually comes to a stop. Select three of the reasons the ball comes to a stop.
A.
Friction and drag oppose the motion of the ball.

B.
There is no force acting to move the ball forward.

C.
The force of friction against the ball is decreased.

D.
The forces opposing the ball are unbalanced.

E.
The force of gravity has increased and stopped the ball.

F.
There was too much inertia to keep the ball rolling.
A. Friction and drag oppose the motion of the ball.
B. There is no force acting to move the ball forward.
D. The forces opposing the ball are unbalanced.