8th: Second Semester Test

A girl pushes on the classroom door to open it. Which choice accurately describes the net force acting on the door?

• Contact & Balanced

• Noncontact & Unbalanced

• Contact & Unbalanced

Two dogs pull on a rope. One dog pulls with a force of 5 N to the left, and the other dog pulls with a force of 3 N to the right. What is the result?

• The rope moves to the left

• The rope has a balanced force applied to it

• The rope moves to the right

Tags

NGSS.MS-PS2-2

A grocery cart has two forces acting on it. 12 N to the right and 4 N to the left. What is the net force on the grocery cart?

• 8 N left

• 16 N left

• 8 N right

Tags

NGSS.MS-PS2-2

Which statement about acceleration is always true?

• Either a change in speed or a change in direction causes acceleration

• Both speed and acceleration must change for acceleration to occur.

• For objects to accelerate, they must speed up

A woman is walking at a rate of 3 miles per hour. What additional information would you need to determine her velocity?

• The gravitational force applied

• The direction she is walking

• The force of her arms swinging

The acceleration of a baseball after it is hit by a bat depends on the mass of the ball and the net force on the ball. This example best illustrates what law?

• Newton's First Law

• Newton's Second Law

• Newton's Third Law

Tags

NGSS.MS-PS2-2

Two school classes are playing tug-of-war with a rope. One class pulls on the rope with a 75 N force to the left, which the other pulls with a 40 N force to the right. Which is true?

• The forces are unbalanced and the net force is 35 N to the right

• The forces are unbalanced and the net force is 115 N to the left

• The forces are unbalanced and the net force is 35 N to the left

Tags

NGSS.MS-PS2-2

Susan ran a 400-m sprint at a track meet, and her final time was 65 seconds. She reported that her velocity in the race was 6.15 m/s. Susan’s statement was inaccurate because she mentioned only speed. She did not include , which is also a part of velocity.

• Direction
• Speed

Pam’s family is clearing some land, and there is a large boulder sitting on top of the ground. Even with the entire family pushing on it, they cannot move it. Which type of friction exists between the boulder and the ground?

• Sliding

• Rolling

• Static

What is the constant for gravity on Earth?

• 9.8 m/s²

• 4.45 Newtons

• 9.8 m/s