Physics Multiple Choice - Midterm Flashcards
Help with midterm
For general projectile motion, the horizontal component of a projectile’s acceleration
Remains a non-zero constant
The average velocity of a car traveling with a constant acceleration during a certain time interval is equal to the mean of the velocities at the beginning and end of that time interval. (T/F)
T
Suppose that an object is moving with constant acceleration. Which of the following is an accurate statement concerning its motion?
In equal times its velocity changes by equal amounts
A rock is thrown upwards at an angle of 40° with respect to the horizontal. As the rock is rising in its trajectory, the horizontal component of its velocity
remains the same
A boy kicks a football with an initial velocity of 20m/s at an angle of 25° above the horizontal. The magnitude of the acceleration of the ball while it is in flight is
9.8m/s^2
When a parachutist jumps from an airplane, he eventually reaches a constant speed, called the terminal velocity. This is an example of
All of Newton’s laws apply to this situation
Force is a vector quantity. (T/F)
T
Mass is a measure of how difficult it is to change the velocity of an object. (T/F)
T
A force is required for an object to move. (T/F)
F
An object always moves in the direction of the net force pushing on it (T/F)
F
It is possible to have zero acceleration, and still be moving. (T/F)
T
An object is in free fall as soon as it is released, whether it is dropped from rest, thrown downward, or thrown upward. (T/F)
T
An object thrown downward does not experience free fall. (T/F)
F
When the velocity and acceleration of an object have the same sign, the speed of the object increases. (T/F)
T
Free fall is the motion of an object subject only to the influence of gravity. (T/F)
T
When is the average velocity of an object equal to the instantaneous velocity?
only when the velocity is constant
Two objects are thrown vertically upwards simultaneously, one on the surface of Earth and the other on the surface of the Moon. Both have an initial velocity of 20m/s. Both objects will take the same time to reach the highest point of their trajectory. (T/F)
F
The vertical component of the acceleration of a projectile remains constant during the entire trajectory of the projectile. (T/F)
T
If the acceleration vector of an object is directed parallel to the velocity vector,
the object is speeding up
A girl kicks a soccer ball with an initial velocity of 25m/s at an angle of 30° above the horizontal. The horizontal component of the velocity of the ball is described by one of the following statements.
it remains constant during the ball’s flight
The acceleration of an object does not have to be in the same direction as the net force applied to it (T/F)
F
When a ball is thrown upwards, it reaches its maximum height when the force pushing it up is equal to its weight (T/F)
F
The force you exert of Earth is insignificant compared to the force Earth exerts on you (T/F)
T
The mass of an object is fixed, but its weight varies from location to location (T/F)
T
You apply the same force to two objects. Object 1 has mass M and object 2 has mass 5M. The acceleration of object 2 is
one-fifth as that of object 1
A 20-ton truck collides with a 1500lb car and causes a lot of damage to the car. Since a lot of damage is done on the car
the force on the truck is equal to the force on the car
Action - reaction forces are
equal in magnitude but point in opposite directions
A ball is thrown up into the air. At the highest point in its trajectory, the net force on it is
equal to its weight
The force of static friction between two surfaces is parallel to the surface of contact, and in the direction that opposes relative motion (T/F)
T
A constant net force acts on an object. Describe the motion of the object
constant non-zero acceleration
An object is moving with constant velocity. Which of the following statements is true?
The net force on the object is zero
Its more difficult to start moving a heavy carton from rest than it is to keep pushing it with constant velocity, because
μk < μs
When a car goes around a curve, it has a tendency to skid outwards. Is the frictional force between the tires and the ground that keeps the car from skidding kinetic or static?
static
Work done by a force on an object can be a positive or a negative quantity (T/F)
T