physics quizzes 6-10
When a dish falls, will the force on the dish be less if it lands on a carpet than if it lands on a hard floor
Yes, force will be less on a carpet
When a box is lifted straight upward, does gravity do work on it?
Yes, it does negative work.
If you push with the same force on an object for twice as much time, the impulse delivered to the object will be
doubled
A freight train rolls along a track with considerable momentum, if its total mass is doubled and it rolls twice as fast, its momentum will be
four times as much.
Two objects move toward each other. As the objects get closer and closer, the gravitational force between them
increases.
When an object is in a state of weightlessness, that means
it has no support force.
When the speed of a bicycle becomes twice as much, which of the following also doubles?
its momentum
When you toss a projectile sideways, it curves as it falls. It will be an Earth satellite if the curve it makes
matches the curved surface of Earth.
A steel ball is attached to a string and is swung in a circular path in a horizontal plane as illustrated in the accompanying figure. At the point P indicated in the figure, the string suddenly breaks near the ball. If these events are observed from directly above as in the figure, which path would the ball most closely follow after the string breaks?
path B
If the masses of two planets are each somehow doubled, the force of gravity between them
quadruples
As soon as a bowling ball rolls off the edge of a table its horizontal component of velocity
remains constant.
A ball is tossed upward at an angle to the horizontal. Neglecting air drag, the acceleration along its path is
straight downward.
A 45-kg sack is lifted 2 meters from the ground and a 25-kg sack is lifted 3 meters in the same time. Which gains more gravitational potential energy?
the 45-kg sack.
A ball is thrown upward at an angle to the horizontal and caught when it returns to its initial height. Compared with its initial speed and neglecting air resistance, the speed with which it is caught is
the same.
A 20-kg mass moving at a speed of 4 m/s has a momentum of
80 kg m/s
6 kg bicycle moving at 4 m/s brakes to a stop in 2 s. What's the average braking force?
12 N
How much work is done in lifting a 500-N barbell 3 m above the floor in 5 seconds?
1500 J
A projectile is launched upward at an angle of 70° from the horizontal and strikes the ground a certain distance downrange. If air resistance is neglected, for what other angle of launch at the same speed would this projectile land just as far away?
20°
A machine does 500 J of work in 20 s. What is the power of the machine?
25 W
How much net work is done on a 1-kg object when it speeds up from 0 m/s to 8 m/s?
32 J
Compared with driving at 30 km/h, how much distance do you need to stop when you are driving at 60 km/h?
4 times as much distance
A projectile falls beneath the straight-line path it would follow if there were no gravity. How many meters does it fall below this line in the first second?
5 m
A fish swims toward and swallows a smaller fish at rest. If the larger fish has a mass of 5 kg and swims 1 m/s toward a 1-kg fish, what is the velocity of the larger fish immediately after lunch? Ignore the effects of water resistance.
5/6 m/s
Astronauts in the international space station appear to float in space. Which of the following best describes the reason.
Astronauts have no apparent weight in orbit because they are falling together with their space station.
Consider two cases.Case 1: you are balancing a meter stick by supporting the end with the tip of your finger.Case 2: you are balancing a meter stick by supporting the end with the tip of your finger, but now there is a mass attached to the other end.Which is easier?
Case 2
On a rotating disc, ladybug A sits close to the rotational axis while ladybug B sits at the outer edge. Then
Ladybug B has a greater tangential speed, but both have the same rotational speed.
The Moon does not crash into Earth because
Moon has a sufficient tangential speed
If the distance between two asteroids doubled, how would the the gravitational force between those two asteroids be affected?
The force would be a quarter what it was
Why is it important that satellites are launched to altitudes of 150 kilometers or higher?
To avoid air resistance
Inside a freely-falling runaway elevator, your
apparent weight is zero
The bob of a simple pendulum has its maximum kinetic energy at the
bottom of its swing
A nut needs to be tightened with a wrench. Which force shown in the figure will apply the greatest torque to the nut?
case C
When ice skaters draw their arms or legs inward, they
decrease their rotational inertia so as to increase their rotational speed