Science 7 Quiz #3 3rd Quarter

A wooden box is dragged across a pavement with a 10-N force to the left. Which of the following forces could possibly act on the wooden box and affect its motion?

• Friction between the box and the pavement
• Tension between the box and the earth
• Pull of the earth on the pavement
• None of the above

If a horse pulls on a calesa at rest, the calesa pulls back equally as much on the horse. Will the calesa be set into motion?

• No, because the forces cancel each other.
• Yes, because there is a net force acting on the calesa.
• Yes, because there is a time delay between action and reaction.
• Yes, because the horse's pull on the calesa is larger than the calesa's pull on the horse.

Will a 10-kg cart be set into motion if a boy applies 100 N force to it?

• Yes, because there is a net force acting on the cart.
• Yes, because there is a time delay between action and reaction.
• No, because the force applied by the boy is equal to that of the cart.
• No, because the cart's pull on the boy is larger than the boy's push on the cart.

Which of the following situations shows the effects of unbalanced forces?

• A girl sitting on a stationary swing
• A framed family picture hanging on the wall
• A basketball rolling at constant speed along the floor
• A young boy sliding down a waterslide in the waterpark

Which of the following scenario does NOT involve a change in speed?

• An airplane taking off from the runway
• A boy running faster toward the finish line
• A large rock falling off a cliff in a straight path
• A bicyclist moving in a straight line at a constant speed

Which is NOT TRUE about magnetic forces?

• Magnets with opposite poles repel each other.
• Magnets with the same poles attract each other.
• Magnets can attract metallic and plastic objects.
• None of the above.

Which forces are present in a wooden box floating in a river?

• Normal and gravitational forces
• Tension and gravitational forces
• Buoyant and gravitational forces
• Magnetic and gravitational forces

Which is NOT TRUE about unbalanced forces?

• Unbalanced forces keep an object at rest.
• Unbalanced forces can increase an object's speed.
• Unbalanced forces can decrease an object's speed.
• Unbalanced forces can change an object's direction.

The free-body diagram shows four forces acting on an object. Which of the following forces can you exert on the object to balance the forces?

• 17 N, to the right
• 17 N, to the left
• 23 N, to the right
• 23 N, to the left

The free-body diagram shows four forces acting on an object. Which of the following forces can you exert on the object to balance the forces?

• 20 N, to the left
• 20 N, to the right
• 20 N, to the north
• 20 N, to the south