Exam 1A MC

A) 3.7 s

A ball is thrown straight upward from ground level with a speed of 18m/s. How much time passes before the ball strikes the ground if we disregard air resistance?

A) yes

A box with a weight of 100N is at rest. It is then pulled by a 55N horizontal force as shown in the figure below. Will the box move? A) yes B) no C) not enough info to say

C) n<15N

A frog is resting on a sloped tree branch as shown in the picture below. The frog has a weight of 15N. What can you say about the magnitude of the normal force acting on the frog? A) n>15N B) n=15N C) n<15N D) it cannot be determined

D) 30N sin delta

A ring, as seen from above is pulled on by three forces. The ring is not moving. How big is the force F? A) 20N B) 30N cos delta C) 20N sin delta D) 30N sin delta

C) zero

A stalled car is being pushed up a hill by three people and its moving at a constant speed. The net force on the car is A) in the opposite direction of the cars motion B) in the same direction of the car's motion C) zero D) none of the above

B) equal to the tension in rope 1

All three 50kg blocks are at rest. The tension in rope 2 is: A) greater than the tension in rope 1 B) equal to the tension in rope 1 C) less than the tension in rope 1

D) 0.597 m/s2

An apple crate with a weight of 225N accelerates along a frictionless surface as the crate with a force of 14.5N as shown. What is the horizontal acceleration of the crate? A) 1.40m/s2 B) 0.427m/2 C) 1.29m/s2 D) 0.597 m/s2 E) 0.644m/s2

C) continue to move to the right with its speed increasing with time

An object is moving to the right in a straight line. The net force acting on the object is also directed to the right but the magnitude of the force is decreasing with time. The object will: A) continue to move to the right with constant speed B) stop and then begin moving to the left C) continue to move to the right with its speed increasing with time D) continue to move to the right with its speed decreasing with time

D) They are not acting on the same body

Giddy up horsey! A horse pulls on a cart and the cart pulls back on the horse; do these two opposing forces cancel? If they are not careful with the logic, and the physics, you might come to the conclusion that no matter how hard the horse pulls, it can never move the cart. But you know a horse can pull a cart in real life, so where is the flaw in this reasoning? The action and reaction forces do not cancel each other out because: A) the action and reaction forces do not cancel each other out because they are not equal in magnitude in this situation B) they are equal in magnitude, but not precisely opposite in direction C) they are equal in magnitude, opposite direction, but do not act at the same time D) they are not acting on the same body

A) -27m

Maria is at position x=23m. She then undergoes a displacement delta x=-50m. What is her final position? A) -27m B) -50m C) 23m D) 73m

B) 3.1 x 10 -9 N

The centers of a 13kg lead ball and a 70g lead ball are separated by 0.14m. What is the gravitational force between them? A) 3.1 x 10 -6 N B) 3.1 x 10 -9 N C) 4.3 x 10 -11 N D) 4.3 x 10 -9 N

C) 7.5m/s, 2.7m/s

The velocity of a frog is 8m/s at 20 degrees above the horizontal. What are the horizontal Vx and vertical Vy components of the frog's velocity A) 7.3m/s, 2.7m/s B) 7.2m/s, 3.4m/s C) 7.5m/s, 2.7m/s D) 7.5m/s, 3.4m/s

B) the one in the smaller orbit

Two identical satellites have different circular orbits shown. Which has a higher speed? A) the one in the larger orbit B) the one in the smaller orbit C) they have the same speed D) the answer cannot be determined

C) All objects in motion have net forces acting on them

Which one of the following statements concerning Newton's first law of motion is false? A) if no force acts on an object, the objects velocity cannot change B) if no net force acts on an object, the object cannot accelerate C) All objects in motion have net forces acting on them