Gunter the weightlifter can lift a 244.2-kg barbell overhead on Earth. The acceleration due to gravity on the sun is 274 m/s2.
a) Would the barbells be heavier on the sun or on Earth?
Question 34
34.
Gunter the weightlifter can lift a 244.2-kg barbell overhead on Earth. The acceleration due to gravity on the sun is 274 m/s2.
b) How much (in newtons) would the barbells weigh on the sun (if it were possible to stand on the sun without melting)?
Question 35
35.
Sarah, whose mass is 35.66 kg, is on her way to school after a winter storm when she accidentally slips on a patch of ice whose coefficient of sliding friction is 0.084. What force of friction will eventually bring Sarah to a stop?
Question 36
36.
A very light ideal spring of spring constant (force constant) 2.5 N/cm is 15 cm long when nothing is attached to it. It is now used to pull horizontally on a 12.5-kg box on a perfectly smooth horizontal floor. You observe that the box starts from rest and moves 96 cm during the first 1.6 s of its motion with constant acceleration of 0.375 m/s2. How long is the spring during this motion?
Question 37
37.
What is the velocity of a 0.367 kg ball that has a momentum of 2.840 kg·m/s?
Question 38
38.
The circus is moving on to the next town and the last animal to board is a stubborn 1715-kg elephant who refuses to budge. Noah pulls the elephant at a constant speed up the 14.3º incline with a force of 9400N. What is the coefficient of sliding friction between the elephant and the loading platform?
Question 39
39.
Howard, the soda jerk at Bea’s diner, slides a 0.512-kg root beer from the end of the counter to a thirsty customer. A force of friction of 1.389 N brings the drink to a stop right in front of the customer.
a) What is the coefficient of sliding friction between the glass and the counter?
Question 40
40.
Howard, the soda jerk at Bea’s diner, slides a 0.512-kg root beer from the end of the counter to a thirsty customer. A force of friction of 1.389 N brings the drink to a stop right in front of the customer.
b) If the glass encounters a sticky patch on the counter, will this spot have a higher or lower coefficient of friction?
Question 41
41.
A 1150-kg slippery hippo slides down a mud-covered hill inclined at an angle of 13.7° to the horizontal.
a) If the coefficient of sliding friction between the hippo and the mud is 0.086, what force of friction impedes the hippo’s motion down the hill?
Question 42
42.
A 1150-kg slippery hippo slides down a mud-covered hill inclined at an angle of 13.7° to the horizontal.
coefficient of sliding friction is 0.086
b) If the hill were steeper, how would this affect the coefficient of sliding friction?
Accelerations are produced by
masses
accelerations
none of these choices
forces
velocities
How does acceleration of an object change in relation to its mass? It is
inversely proportional.
Acceleration doesn't depend on mass at all.
directly proportional.
The acceleration produced by a net force on an object is
in the same direction as the net force.
all of the choices, except none of the choices
inversely proportional to the mass of the object.
none of the choices
directly proportional to the magnitude of the net force.
A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is
10 times as much as the force on the 1-kg book.
zero.
the same as the force on the 1-kg book.
When a woman stands with two feet on a scale, the scale reads 150 N. When she lifts one foot, the scale reads
150 N
more than 150 N
less than 150 N
Suppose the force of friction on a sliding object is 25 N. The force needed to maintain a constant velocity is
25 N
more than 25 N
less than 25 N
A bowling ball weighs 20 N. When held at rest in your hands, the net force on the bowling ball is
2.0 N
196 N
20 N
0 N
A girl pulls on a 7-kg wagon with a constant force of 14 N. What is the wagon's acceleration?
2 m/s2
7 m/s2
14 m/s2
0.5 m/s2
98 m/s2
An object has a constant mass. A constant force on the object produces constant
both velocity and acceleration
none of these choices
acceleration
velocity
A force of 4 N accelerates a mass of 4 kg at the rate of 1 m/s2. The acceleration of a mass of 8 kg acted upon by a force of 8 N is
none of these choices
twice as much
half as much
the same
A push on a 4-kilogram brick accelerates the brick. Neglecting friction, to equally accelerate a 16-kilogram brick, one would have to push
with 1/4 the amount of force
with 40 times as much force
with just as much force
none of these choices
with 4 times as much force
A toybox is dragged without acceleration in a straight-line path across a level surface by a force of 11 N. What is the frictional force between the toybox and the surface?
11 N
More than N
Need more information to say.
Less than N
Suppose a particle is accelerated through space by a constant 10-N force. Suddenly the particle encounters a second force of 10-N in a direction opposite to that of the first force. The particle
is brought to a rapid halt.
continues at the speed it had when it encountered the second force.
gradually decelerates to a halt.
theoretically accelerates to speeds approaching the speed of light.
none of these choices
A tennis ball and a solid steel ball with the same diameter are dropped at the same time. Which ball has the greater force acting on it?
The tennis ball
The steel ball
They both have the same force acting on them.
A tennis ball and a solid steel ball with the same diameter are dropped at the same time. In the absence of air resistance, which ball has the greater acceleration?
They both have the same acceleration.
The tennis ball
The steel ball
The reason a tennis ball and a solid steel ball will accelerate at the same rate, in the absence of air resistance, is that
none of these choices
the ball with the larger force also has the larger mass.
the force acting on them is the same.
they have the same mass.
the ball with the larger force has the smaller mass.
As a care package falls from a high-flying stationary helicopter, its velocity increases and its acceleration
increases.
remains the same.
decreases.
If you pull horizontally on a desk with a force of 150 N and the doesn't move, the friction force must be 150 N. Now if you pull with 270 N so the slides at constant velocity, the friction force is
more than 270 N
270 N
more than 150 N but less than 270 N
When the angle of an incline with a block resting on it increases, the normal support force
increases
decreases
remains the same
Consider a ball rolling down the decreasing slope inside a semicircular bowl (the slope is steep at the top rim, gets less steep toward the bottom, and is zero (no slope) at the bottom). As the ball rolls from the rim downward toward the bottom, its rate of gaining speed
remains the same
decreases
increases
A block is at rest on an incline. The force of friction necessary to prevent the block from sliding increases when the incline angle is
decreased
increased
neither A nor B (Force of friction stays the same.)
If the force acting on a cart doubles, what happens to the cart's acceleration?
it halves
it remains the same
it quadruples
it quarters
it doubles
Suppose a cart is being moved by a 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 doubles
it quadruples
it remains the same
it halves
it quarters
A tow truck exerts a force of 1000 N on a car, accelerating it at 0.5 m/s2. What is the mass of the car?
none of these choices
1000 kg
667 kg
2000 kg
4000 kg
A 8-N falling object encounters 8 N of air resistance. The magnitude of the net force on the object is
0 N
none of these choices
16 N
8 N
If you pound a feather with a hammer, which one feels a greater force?
always the feather
The size of the force is always exactly the same on both of them.
If the feather moves, then it felt the greater force. Otherwise the force was the same on both.
always the hammer
An elevator suspended by a vertical cable is moving downward but slowing down. The tension in the cable must be
less than than the weight of the elevator.
equal to the weight of the elevator.
greater than the weight of the elevator.
Bill and his daughter Susan are both standing on identical skateboards (with really good frictionless ball bearings), initially at rest. Bill weighs three times as much as Susan. Bill pushes horizontally on Susan's back, causing Susan to start moving away from Bill. Just after Bill stops pushing,
Susan and Bill are moving away from each other, and Susan's speed is one-third that of Bill.
Susan is moving away from Bill, and Bill is stationary.
Susan and Bill are moving away from each other, and Susan's speed is three times that of Bill.
Susan and Bill are moving away from each other, with equal speeds.
A 20-ton truck collides with a 1500-lb car. Which of the following statements must be true?
The car did not slow down during the collision, but the truck did.
During the collision, the force on the truck is greater then the force on the car.
During the collision, the force on the truck is smaller than the force on the car.
During the collision, the force on the truck is equal to the force on the car.
The truck did not slow down during the collision, but the car did.
You are standing in a moving bus, facing forward, when you suddenly slide forward as the bus comes to an immediate stop. What force caused you to slide forward?
There is not a force causing you to slide forward.
gravity
the force due to friction between you and the floor of the bus
the normal force due to your contact with the floor of the bus
In the figure, a 10-lb weight is suspended from two spring scales, each of which has negligible weight. Which one of the following statements about the readings in the scales is true?
None of these is true.
Each scale will show a reading between one and 10 lb, such that the sum of the two is 10 lb. However, exact readings cannot be determined without more information.
Each scale will read 5 lb.
The top scale will read zero, the lower scale will read 10 lb.
The lower scale will read zero, the top scale will read 10 lb.
A push of magnitude P acts on a box of weight W as shown in the figure. The push is directed at an angle theta(𝚹) below the horizontal, and the box remains a rest. The box rests on a horizontal surface that has some friction with the box. The normal force on the box due to the floor is equal to