Physics force quiz

Net Force =

Mass x Acceleration or pull/pull-friction(fk)

If you are moving, is there any way you can tell whether you are moving up or down? If so, how?

No (we can't feel motion/velocity, only feel acceleration)

Is there any way you can tell whether you are stationary versus moving at a constant velocity? If so, how?

No (we can't feel motion/velocity, only feel acceleration)

Suppose a cart is being moved by a constant force. If suddenly a load is dumped into the cart so that the cart's mass doubles, what happens to the cart's acceleration?

it halves

normal force for vertical =

just px (cos)

Weight =

mass x gravity

Friction =

pull/push - net force or Mk (coefficient thing) x normal force

A jumbo jet cruises at a constant velocity when the total thrust of the engines on the jet is 40,000N. How much air resistance acts on the jet?

40000 N

The reason a tennis ball and a solid steel ball will accelerate at the same rate, in the absence of air resistance, is that a) the ball with the larger force also has the larger mass b) they have the same mass c) the ball with the larger force has the smaller mass d) the force acting on them is independent of mass e) none of the above

A

If the net force acting on an object is zero, which of the following must be true? a) There are no forces acting on the object. b) The object is not moving. c) The object is not accelerating. d) The object has no friction acting on it. e) More than one of the above must be true.

C

As a sky diver falls faster and faster through the air (before reaching terminal speed), the acceleration

Decreases

A rock is thrown vertically into the air. As the rock is moving upward, the net force is

Equal to its weight

Acceleration =

Fnet/mass = m/s^2

Friction

Friction is a force that holds back the movement of a sliding object.

A woman is standing on a scale in an elevator. The scale reads less than her actual weight. What does this tell you?

The women is accelerating downward

The force required to maintain an object at a constant speed in free space is equal to ...

Zero

A hapless physics student conducts an experiment while flying on an airplane. The student throws a coin straight up in the air. The coin flies to the back of the airplane. The student concludes that Newton's first law is incorrect. Which of the following explains the hapless physics student's error? a) The airplane must be accelerating, so the student is not in an inertial reference frame. b) The student did not account for the air resistance the coin encountered on the airplane. c) The airplane applied a force to the coin, knocking it backwards. d) The plane's velocity is forward, so the coin has an equal but opposite velocity. e) The student did not make an error; Newton's first law is thus incorrect.

a

An orange might roll off your cafeteria tray when you stop suddenly because

a) There is not enough of a force on the orange to keep it on the tray.

If the sun somehow disappeared suddenly, the planets would

a) move in a straight line tangent to their orbit.

net force and acceleration are...

always in the same direction

Net Force

ector sum of all the forces that act upon an object. (sum of all forces)

Acceleration

the rate of change in velocity per unit of time, undergo a change in velocity

Velocity

the speed of something in a given direction.

normal force for horizontal =

weight - py

equilibrium

where opposing forces are balanced