Physics
A bullet is fired horizontally at a target 20 m away. The velocity of the bullet as it leaves the gun is 100 m/s. How much, approximately, will the bullet drop on its way to the target?
0.2 M
Assuming g = 10 m/s2 and that air resistance is negligible, in 1/2 second a ball dropped from rest will fall:
1.25 meters.
A book weighing 10 N is held at rest in the palm of the hand. The reaction to the force of the hand on the book is a force of:
10 N exerted by the book on the hand.
A block of mass 5.0 kg is acted upon by a single force, producing an acceleration of 2.0 m/s2. The force has a value of:
10 N.
A ball is projected straight up with an initial velocity of 20 m/s. After 1 second, its velocity will be:
10.2 m/s.
Your weight is 100 lb. Suppose you are standing on a scale in an elevator moving up with a constant speed of 3 m/s. What would be the reading on the scale?
100lb
Suppose one's hand exerts a force of 12 N upward on a book weighing 10 N. The reaction to the force of the hand on the book is a force of:
12 N exerted by the book on the hand.
An iron vise falls from rest at a great height. Neglecting air resistance, what distance has it fallen in the first 5 seconds?
122m
A crate is acted upon by a net force of 100 N. An acceleration of 5.0 m/s2 results. The weight of the crate is:
196 N.
A ball is projected upward with an initial velocity of 20 m/s. It will reach its maximum height in approximately:
2 sec
A 10 kg object dropped from a certain window strikes the ground in 2.0 s. Neglecting air resistance, a 5 kg object dropped from the same window strikes the ground in:
2.0 s.
In order to find the depth of a well, you drop a stone into it and time its fall. It hits the water after falling for 2 s. The depth of the well is about:
20M
The surface gravity of Mars is 3.7 m/s2. If a person with mass of 100 kg were parachuting on Mars, what would be the force exerted by air resistance at terminal velocity?
370 N
Suppose you throw a ball vertically upward with a speed of 49 m/s. Neglecting air friction, what would be the speed of the ball one second later?
39.2 m/s
Your mass is 50 kg. Suppose you are standing on a scale in an elevator, that is approaching a top floor and decreasing its speed at the rate of 2 m/s every second. What would be a reading on the scale?
390 N
After 1 second, a ball dropped from rest will have fallen:
4.9M
A stone is thrown upward from a bridge at a speed of 10 m/s. It narrowly misses the bridge on the way back down, and hits the water at 30 m/s. The bridge is about:
40 m high
A man standing on a bridge throws a stone horizontally with a speed of 20 m/s. The stone hits the water below 3 s later. The bridge is:
45 meters high
An iron vise falls from rest at a great height. Neglecting air resistance, what is its speed after it has fallen for 5 seconds?
49 m/s
During the first 10 seconds after a ball is dropped from rest, how far will it fall?
490 M
A parachutist jumping from an airplane reaches a terminal velocity when the force of air resistance is 490 N. The mass of the parachutist is:
50 kg.
A child, whose weight is 150 newtons, lifts a pumpkin from the ground with a force of 50 newtons. The force the pumpkin exerts on the child is:
50 newtons.
A dog weighs 250 N. What is his approximate weight in pounds (lb)?
55 lb
Your mass is 50 kg. Suppose you are standing on a scale in an elevator which starts moving up and increases its speed at the rate of 2 m/s every second. What would be the reading on the scale?
590N
An elevator of mass 500 kg is caused to accelerate upward at 4.0 m/s2 by a force in the cable. What is the force exerted by the cable?
6,900 N
A 5.0 kg block on a smooth horizontal surface is acted upon by two forces: a horizontal force of 40 N acting to the right and a horizontal force of 10 N to the left. The acceleration of the block will be:
6.0 m/s2 to the right
A car rounds a curve while maintaining constant speed. The correct statement is:
A net force acts upon the car.
A ball is thrown straight up. It reaches its highest point and then falls back. Which of the following is the correct statement?
At the highest point in its motion, the ball's velocity is zero.
In a laboratory on Earth, all the air is pumped from a large tube. A feather and a steel ball are simultaneously released from rest inside the tube. What happens next?
Both objects fall and hit the bottom at the same time
A net horizontal force of 200 N acts on a 50 kg cart, which is free to roll on a level surface.
The cart accelerates at 4 m/s2.
A ball is thrown across the street. During its flight, the ball's speed is lowest at:
The highest point of its flight.
The force that accelerates a car on a level road is exerted by which object?
The road
A 10 pound iron ball and a 2 pound iron ball are dropped simultaneously from a height of 100 meters. Neglecting air resistance, which ball will reach the ground first?
They will reach the ground at the same time
For a body moving with constant acceleration, which of the following graphs will be a straight line?
Velocity versus time
A common experience is to find that a steady pull is required to keep an object moving, even on a level surface with friction present. Analyzing this experience in light of the laws of motion, the accepted conclusion is that:
a frictional force exactly opposes your pull and the first law applies.
A body sliding on a table is observed to gradually slow down. The correct statement is that the body slows down because:
a net force acts on the body.
A certain force causes a 50 kg person to accelerate at 1.0 m/s2. The same force applied to a 75 kg person would cause:
a smaller acceleration.
Neglecting friction, if a Cadillac and Volkswagen start rolling down a hill together, the heavier Cadillac will get to the bottom:
at the same time as the Volkswagen.
A person standing at the edge of a cliff throws one ball straight up and another ball straight down at the same initial speed. Neglecting air resistance, the ball which hits the ground at the base of the cliff with the greater speed is the one initially thrown:
both hit with the same speed.
A rifle bullet is fired horizontally at the same instant another bullet is allowed to drop from rest at the same height. Which bullet strikes the earth first?
both strike at the same instant
A football is thrown upward at some angle above the horizontal. If we neglect air friction, then we can conclude that the acceleration vector of the football is:
down
A body released from rest falls with an acceleration of 9.8 m/s2. If the same body is thrown upward at an angle, and air resistance is negligible, its acceleration will be:
downward, and equal to 9.8 m/s2.
If you drop a ball in the absence of air resistance, it accelerates downward at 9.8 m/s2. If instead you throw the ball upward, then its acceleration after release is
equal to 9.8 m/s2.
An object rises at 5 m/s under the influence of gravity only. One second later the object is:
falling at 5 m/s.
The frictional force, due to air resistance, acting on an object is always:
in the opposite direction to the objects motion.
A bullet is fired straight down from a hovering helicopter. If we neglect air friction, then the velocity of the bullet:
increases at 9.8 m/s each second.
A single constant 10 pound force F1 acts on a body, causing it to accelerate. Then, while F1 continues to act, a second constant force F2 is applied to the body, which comes to a momentary stop. The magnitude of F2 is:
larger than 10 pounds.
Two blocks of equal mass are connected by a string. The system is accelerated across a smooth horizontal surface by a force supplied by a rubber band connected to the leading block. The tension in the connecting string will be:
less than the force pulling the leading block.
A ball rolls off a shelf and hits the floor below 0.25 seconds later. To find the speed of the ball as it left the shelf, we would need:
the distance measured along the floor to the point of impact.
A block, moving on a frictionless horizontal surface on Earth, requires a force if it is to be stopped. Now suppose that the same block, moving with the same speed on a frictionless horizontal surface on the Moon where gravity is less, is to be stopped in the same time. We can say that, compared to the Earth,
the force required would be the same.
You stand on a scale to measure your weight. The reaction to the force the Earth exerts on you is:
the force you exert on the Earth.
Two bodies have quite different masses, but the net force applied to each of them is the same. The acceleration of:
the less massive body is larger.
The acceleration of gravity on the moon's surface is about 1/6 of that on the Earth's surface. An object on the Earth is to be taken to the Moon. We can state that, compared to the Earth,
the object's mass will be the same on the Moon.
A ball thrown upward reaches its maximum height, and then falls back. If air resistance is negligible, its acceleration is:
the same at all points in the motion.
An elevator is being lifted upward at a constant speed by a steel cable. All frictional forces are neglected. In this situation, forces on the elevator are such that:
the upward force by the cable is equal to the downward force of gravity.
All except one of the following require the application of a net force. Which one is the exception?
to maintain an object in motion at a constant velocity
You toss a ball straight up in the air. At the highest point, the ball's:
velocity is zero and the acceleration is downward.
(Ignore air friction for this problem.) Two identical balls are thrown simultaneously from the top of a very tall cliff. Ball A is thrown downward with an initial velocity of 6 m/s, while ball B is thrown straight upward with an initial velocity of 9.8 m/s. After one second has elapsed, the:
velocity of ball B is zero.
The acceleration of a body is given by the slope of a graph plotting:
velocity versus time.
A 100 pound sack of potatoes falls from an airplane. As the velocity of the falling sack increases, so does the air resistance on it. When the air resistance equals 100 pounds, the acceleration of the sack will be:
zero.