CFA/Forces and Motion

If Shane and Susan both push on a box with a force of 25N, but in opposite directions, what will happen to the box?

• A)The box will not move.

• B)The box will slide toward Shane.

• C)The box will slide toward Susan.

• D)The box will be perpendicular to both Shane and Susan.

A spring balance attempts to drag an object across a table, but the object does not move because of the force of friction acting on the body in an equal and opposite direction. When the forces acting upon an object are equal and opposite the object is said to be in a state of equilibrium.What are these forces called?

• A)Even forces

• B)Balanced forces

• C)Harmonized forces

• D)Unbalanced forces

Newton's second law states that F = m x a (Force is mass times acceleration). Which example would have the GREATEST acceleration?

• A)a 10 kg ball thrown with a 50 Newton force

• B)a 1 kg ball thrown with a 0.5 Newton force

• C)a 50 kg student launched by a 100 Newton catapult

• D)a 500 kg car accelerated by 1000 Newtons from the engine

Meg and Rachel each have bowling balls with the same mass. They both roll them as hard as they can and then measure the speed of the balls.Meg's ball and Rachel's ball were measured to have the exact same speed.What do you know about the forces applied by the girls?

• A)Meg applied more force than Rachel.

• B)Rachel applied more force than Meg.

• C)They applied an equal amount of force.

• D)They applied a almost the same amount of force.

A driver sets his cars cruise control on a flat highway, causing the car to travel at a constant velocity. Which is true in this situation?

• A)The cruise control decreases friction.

• B)The cruise control causes the car to experience an unbalanced force.

• C)The force from the driver's foot is needed to keep the car from stopping.

• D)The force of friction is balanced out by the forward force applied by the engine.

A 600g basketball, a 500g football, a 150g baseball, and a 50g yo-yo: four toys. If you had to throw one of the four, which one would take the MOST force to throw?

• A)baseball

• B)basketball

• C)football

• D)yo-yo

Lin and Erin decide to have a tug of war contest. Erin pulls the rope with all her might and so does Lin. Sadly, Lin only pulls with half the force that Erin pulls with. Which way will the rope move?

• A)towards Erin, since the forces are balanced

• B)towards Lin, since the forces are balanced

• C)towards Erin, since the forces are unbalanced

• D)towards Lin, since the forces are unbalanced

Acceleration increases over time once a force is applied to the object. Given a force of 10.0 Newtons, which mass will have the greatest acceleration?

• A)0.10 kg beach ball

• B)2.0 kg brick

• C)5.0 kg steel block

• D)10.0 kg bag of feathers

Determine the weight of an average physical science textbook whose mass is 3.1 kilograms. The acceleration due to gravity is 9.8m/s2. Hint: W= mg

• A)0.32 Newtons

• B)3.1 Newtons

• C)6.82 Newtons

• D)30.4 Newtons

An experiment was performed on a 2-kg block. Forces of 5, 10 and 15 Newtons respectively were applied to the block for 5 seconds. Describe the difference in acceleration between the three trials.

• A)The final accelerations will all be the same.

• B)The final acceleration will triple between the first and third trial.

• C)The final acceleration will be cut by 1/3 from the first to third trial.

• D)The final acceleration will increase nine time between the first and third trial.