Physics 31N: Newton’s First Law
Two forces have the same magnitude F.
What is the angle between the two vectors if their sum has a magnitude of 2F? θ = 0∘
What is the angle between the two vectors if their sum has a magnitude of 2√F? θ = 90∘
What is the angle between the two vectors if their sum has a magnitude of zero? θ = 180∘
An object is moving in the absence of a net force. Which of the following best describes the object's motion? *The object will continue to move with a constant velocity.
An object is moving with constant velocity. Which of the following best describes the force(s) acting on the object? *The net force acting on the object is zero.
A constant net force acts on an object. Which of the following best describes the object's motion? *The object is moving with a constant acceleration.
The same net force is applied to two different objects. The second object has twice the mass of the first object. Compare the acceleration of the two objects. *The acceleration of object 1 is twice the acceleration of object 2.
An object is at rest on a tabletop. Earth pulls downward on this object with a force equal in magnitude to mg. If this force serves as the action force, what is the reaction force in the action–reaction pair? *The object pulling upward on Earth
A large truck collides head-on with a small car. The car is severely damaged as a result of the collision. According to Newton's third law, how do the forces acting between the truck and car compare during the collision? *The force on the truck is equal to the force on the car.
You swing a bat and hit a heavy box with a force of 1500 N. The force the box exerts on the bat is *Exactly 1500 N whether or not the box moves.
A stalled car is being pushed up a hill at constant velocity by three people. The net force on the car is *Zero
In order to get an object moving, you must push harder on it than it pushes back on you. *False
In order to lift a bucket of concrete, you must pull up harder on the bucket than it pulls down on you. *False
A box of mass m is pulled with a constant acceleration a along a horizontal frictionless floor by a wire that makes an angle of 15° above the horizontal. If T is the tension in this wire, then *T>ma
You are standing in a moving bus, facing forward, and you suddenly fall forward as the bus comes to an immediate stop. The force acting on you that causes you to fall forward is *No forces were acting on you to cause you to fall.
Consider what happens when you jump up in the air. Which of the following is the most accurate statement? *When you push down on the earth with a force greater than your weight, the earth will push back with the same magnitude force and thus propel you into the air.
A fish weighing 16 N is weighed using two spring scales, each of negligible weight, as shown in the figure. What will be the readings of the scales? [pic]
*Each scale will read 16 N
An object is moving forward with a constant velocity. Which statement about this object MUST be true? *The net force on the object is zero.
A ball is tossed vertically upward. When it reaches its highest point (before falling back downward) *The velocity is zero, the acceleration is directed downward, and the force of gravity acting on the ball is directed downward.
A car is being towed at constant velocity on a horizontal road using a horizontal chain. The tension in the chain must be equal to the weight of the car in order to maintain constant velocity. *False
Two dogs pull horizontally on ropes attached to a post; the angle between the ropes is 61.0∘. Dog Aexerts a force of 282N and dog B exerts a force of 312N.
Find the magnitude of the resultant force.
F = 512 N
Find the angle the resultant force...
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