Physics Midterm

A lead block is suspended from your hand by a string. The reaction to the force of gravity on the block is the force exerted by the:

block on the Earth

A feather and a lead ball are dropped from the rest in vacuum on the Moon. The acceleration of the feather is:

the same as that of the lead ball

A vector of magnitude 3 cannot be added to a vector of magnitude 4 so that the magnitude of the resultant is:

zero

A vector has a magnitude of 12. When its tail is at the origin it lies between the positive x axis and negative y axis and makes an angle of 30 degrees with the x axis. Its y component is:

-6

A crane operator lowers a 16,000 N steel ball with a downward acceleration of 3 m/s^2. The tension in the cable is:

11,000 N

A 6 kg object is moving south. A net force of 12 N north on it result in the object having an acceleration of:

2 m/s^2 north

A ball is thrown horizontally from the top of a 20-m high hill. it strikes the ground at an angle of 45 degrees. How long was the ball in the air?

2.0 s

A car, initially at rest, travels 20 m in 4 s along a straight line with constant acceleration. The acceleration of the car is:

2.5 m/s^2

A 2000 kg elevator is rising and its speed is increasing at 2 m/s^2. The tension in the elevator cable is:

24,000 N

A car starts from rest and goes down a slope with a constant acceleration of 5 m/s^2. After 5 seconds the car reaches the bottom of the hill. Its speed at the bottom of the hill, in meters per second, is:

25

A racing car traveling with constant acceleration increases its speed from 10 m/s to 30 m/s over a distance of 60 m? How long does this take?

3.0 s

Neglecting the effect of air resistance a stone dropped off a 175-m high building lands on the ground in

6 s

A stone thrown outward from the top of 59.4-m high cliff with an upward velocity component of 19.5 m/s. How long is stone in the air?

6.00 s

The inertia of a body tends to cause the body to:

resist any change in its motion

A bullet shot horizontally from a gun:

strikes the ground approximately the same time as one dropped vertically from the same point at the same instant

A freely falling body has a constant acceleration of 9.8 m/s^2. This means that:

the speed of the body increases by 9.8 m/s during each second

A heavy ball is suspended as shown. A quick jerk on the lower string will break that string but a slow pull on the lower string will break the upper string. The second result occurs because:

The ball has weight

A stone thrown from the top of a tall building follows a path that is:

a straight line

An object rests on a horizontal friction-less surface. A horizontal force of magnitude F is applied. This force produces an acceleration:

always

A baseball is thrown vertically into the air. The acceleration of the ball at its highest point is:

g, down

You stand on a spring scale on the floor of an elevator. Of the following, the scale shows the highest reading when the elevator:

moves downward with decreasing speed

A circus performer of weight W is walking along a "high wire" as shown. The tension in the wire is:

much more than W

A vector S of magnitude 6 and another vector T have a resultant of magnitude 12. The vector T:

must have a magnitude of at least 6 but no more than 18

Acceleration is always in the direction:

of the net force

An object is shot from the back of a railroad flatcar moving at 40 km/hr on a straight horizontal road. The launcher is aimed upward, perpendicular to the bed of the flatcar. The object falls:

on the truck

Acceleration is defined as:

rate of change of velocity with time

A car starts from Hither, goes 50 km in straight line to Yon, immediately turns around, and returns to Hither. The time for this round trip is 2 hours. The magnitude of the average velocity of the car for this round trip is:

0 km/hr

a 25 kg crate is pushed across a friction-less horizontal floor with a force of 20 N, directed 20 degrees below the horizontal. The acceleration of the crate is:

0.75 m/s^2

A ball with weight of 1.5 N is thrown at an angle of 30 degrees above the horizontal with an initial speed of 12 m/s. At its highest point, the net force on the ball is:

1.5 N down

A boat is able to move through still water at 20 m/s. it makes a round trip to a town 3.0 km upstream. If the river flows at 5 m/s, the time required for the round trip is:

320 s

How far does a car travel in 6 s if its initial velocity is 2 m/s and its acceleration is 2 m/s^2 in the forward direction

48m

A boat is rowed at 5 km/hr west across the Mississippi River which flows at 2 km/hr south. What is the resultant speed of the boat?

5 km/hr

When a certain force is applied to the 1-kg standard mass its acceleration is 5.0 m/s^2. When the same force is applied to another object its acceleration is one-fifth as much. The mass of the object is:

5.0 kg

A block slides down a friction-less plane that makes an angle of 30 degrees with the horizontal. The acceleration of the block is:

5.00

A boy on the edge of a vertical cliff 20 m high throws a stone horizontally outwards with a speed of 20 m/s. It strikes the ground at what horizontal distance from the foot of the cliff?

50 m

A vector in the xy plane has a magnitude of 25 and an x component of 12. The angle it makes with the positive x axis is:

61 degrees

A car moving with an initial velocity of 25 m/s north has a constant acceleration of 3 m/s^2 south. After 6 seconds its velocity will be:

7 m/s north

A large cannon is fired from the ground level over level ground at an angle of 30 degrees above the horizontal. The muzzle speed is 980 m/s. Neglecting air resistance, the projectile will travel what horizontal distance before striking the ground?

8.5 km

Identical guns fire identical bullets horizontally at the same speed from the same height above level planes, one on the Earth, where g=10 m/s^2, and one on the Moon, where g=5/3 m/s^2. This means that:

The horizontal distance traveled by the bullet is greater for the Moon & The flight time is less for the bullet on the Earth

the position-time graph of an object is a straight line with a positive slope. The object has:

constant velocity

The mass of a body:

is independent of the acceleration due to gravity

An object is shot vertically upward. While it is rising:

its velocity is upward and its acceleration is downward

A newton is the force:

that gives a 1 kg body an acceleration of 1 m/s^2

an object has a constant acceleration of 3 m/s^2. The displacement versus time graph for this object has a slope:

that increases with time

a feather initially at rest is released in a vacuum 12 m above the surface of the Earth, which means that:

the acceleration of the feather remains constant during the fall

Displacement can be obtained from

the area under a velocity-time graph

The average speed of a moving object during a given interval of time is always:

the distance covered during the time interval divided by the time interval

A heavy steel ball B is suspended by a cord from a block of wood W. The entire system is dropped through the air. Neglecting air resistance, the tension in the cord is:

zero