Forces REVIEW Two forces 360 N and 120

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Forces REVIEW

Forces REVIEW

�Two forces, 360 N and 120 N are applied to a sled on a

�Two forces, 360 N and 120 N are applied to a sled on a frictionless surface. �Determine how to achieve the maximum force? What would the net force be in that situation? �Determine how to achieve the minimum force? What would the net force be in that situation?

Answers �To achieve the MAXIMUM net force, apply the forces in the SAME direction

Answers �To achieve the MAXIMUM net force, apply the forces in the SAME direction giving a net force of 480 N. �To achieve the MINIMUM net force, apply the forces in OPPOSITE directions giving a net force of 240 N.

�Two blocks are placed on a horizontal surface and pulled by a rope to

�Two blocks are placed on a horizontal surface and pulled by a rope to the right with a force of 15. 0 N. One of the blocks has a mass of 2. 0 kg and the other has a mass of 3. 0 kg. �What is the acceleration of the blocks if there is NO friction? �What is the acceleration of the blocks if there is a 5. 0 N frictional force?

Answers �No friction = 3 m/s 2 �With friction = 2 m/s 2

Answers �No friction = 3 m/s 2 �With friction = 2 m/s 2

� Compare and contrast the following… �Thrust and Tension �Weight and Normal Force �Vector

� Compare and contrast the following… �Thrust and Tension �Weight and Normal Force �Vector and Scalar

Answers �Thrust is the applied force from an engine or person and tension is

Answers �Thrust is the applied force from an engine or person and tension is the force applied by a rope, string or cable. �Weight is the downward force of gravity and normal force is the perpendicular upward force exerted by a surface. �Vectors have magnitude and direction and scalars only have magnitude.

� What is the net force acting on an object in equilibrium?

� What is the net force acting on an object in equilibrium?

Answer �ZERO

Answer �ZERO

� A child who weighs 75 N sits on a tire swing. If the

� A child who weighs 75 N sits on a tire swing. If the tire weighs 65 N, what is the tension in the rope holding the tire swing up?

Answer � 140 N

Answer � 140 N

� Define terminal velocity.

� Define terminal velocity.

Answer �The constant velocity reached when weight equals friction due to air resistance (air

Answer �The constant velocity reached when weight equals friction due to air resistance (air drag).

�Draw free body diagrams for the following situations… �A bike accelerates on a horizontal

�Draw free body diagrams for the following situations… �A bike accelerates on a horizontal road without friction. �A bike accelerates on a horizontal road with friction. �A coffee mug sits motionless on a table. �Two men push a car accelerating it to the right.

� An astronaut travels to the moon. His weight is ____ and his mass

� An astronaut travels to the moon. His weight is ____ and his mass is _____.

Answers �Weight is LESS but mass is THE SAME.

Answers �Weight is LESS but mass is THE SAME.

� What is the weight of a truck that has a mass 9 of

� What is the weight of a truck that has a mass 9 of 1. 75 x 10 kg?

Answer � 1. 72 x 1010 N

Answer � 1. 72 x 1010 N

� What is the weight of an elephant that has a mass of 975.

� What is the weight of an elephant that has a mass of 975. 0 kg?

Answer � 9555 N

Answer � 9555 N