Physic 2
A 900N man is playing on a seesaw with son who has a weight of 100N. If the child is sitting 3 meters away how far will the man have to sit to balance the seesaw?
1/3 meters
A block is sliding on a rough surface with coefficient of kinetic friction µk= 0.1. The weight of the block is 100 N, calculate the magnitude of the force of kinetic friction.,
10 N
What is the acceleration of the following system?
10 m/s^2 to the right
A 8 kg ball is rolling on a flat surface with a speed of 5 m/s. The objects kinetic energy is
100 J
What is the acceleration of the following system? 4 kg, 3kg, 80n, 2n, 8n
10m/s2
A roller coaster of mass m = 50 kg is at rest at its top point A, which has a height h = 10 m above ground. The roller coaster then starts sliding down the track. What is its final velocity when it reaches the ground at C? (We can neglect the friction as the coaster runs on ice)
14 m/s
A 30 kg bike accelerated at 5 m/s2. what was the force acting on the bike?
150 N
Two masses of mass 10.0 and 6.0 kg are hung from massless strings at the end of a light rod. The rod is virtually weightless. A pivot (fulcrum) is placed off-center and the system is free to rotate. If the 6.0 kg mass is 4.0 m away from the pivot;how far away is the 10.0 kg mass if the system is not rotating?
2.4m
When a certain force is applied to an object with a mass of 2 kg; the object's acceleration is 10.0 m/s2. What is the applied force?
20 N
Which of the following answers is closest to the weight (on the Earth's surface) of a woman whose mass is 20kg? consider gravitational acceleration as ~ 10 m/s2
200 N
Larry's total energy (KE + PE + Thermal Energy) is 2000 J as he reaches 100 m above the ground in a sky diving airplane. What is Larry's gravitational potential energy when he begins to jump at rest from the airplane at an altitude of 1000 m?
2000 J
A 100-N force is applied at the end of a wrench handle that is 25 cm long. The force is applied in a direction perpendicular to the handle as shown. What is the torque applied to the nut by the wrench?
25 Nm
The net force on the following system is
4000 N , left (engine 60n,car 100n, trailer 100n)
The net force on the following system is(car engine trailer)
4000 N, left
In the absence of air resistance, the angle at which a thrown ball will do the farthest is
45 degrees
When a certain force is applied to an object with a mass of 2 kg; its acceleration is 10.0 m/s2. When the same force is applied to a different object; its acceleration is 4.0 m/s2. The mass of the second object is ( note: the problem is two-step process)
5 kg
A roller coaster of mass m = 50 kg is at rest at its top point A, which has a height h = 10 m above ground. The roller coaster then starts sliding down the track. What is its total mechanical energy at the point B? (We can neglect the friction as the coaster runs on ice)
5000 j
A roller coaster runs on a rough surface (FRiction can not be neglected). The mass of the roller coaster is 50 kg and it is at rest at its top point A, which has a height h = 10 m above ground. The roller coaster then starts sliding down the track. What is its total mechanical energy at points B and C?
5000 j
An object accelerates 8 m/s2 when a force of 56 N is applied to it. What is the mass of the object?
7 kg
The net force on the following system is
70 N to the right
An object with a mass of 5 kg has a force of 40 N applied to it. What is the resulting acceleration of the object?
8 m/s/s
Calculate the weight (on the Moon's surface) of a woman whose mass is 55 kg. Consider gravitational acceleration on Moon as ~ 1.62 m/s²
89 N
A constant force F acts on block 1 with mass m (ex. 50 kg). The same constant force F acts on block 2 with same mass (50 kg). Which graph correctly represents the accelerations of the blocks?
A
Two spherical objects are released from the same height (neglect air resistance). Object A falls straight down from the cliff and object B follows a curved parabolic path. It is true that:
A and B hit the ground at the same time.
Assume that a car is traveling on a road. The coefficient of friction μbetween the tires and the asphalt depends on
All of the above
To increase the applied torque one can -Increase the lever arm by applying the force perpendicularly to the lever -Increase the lever arm by moving to the end of the lever -Increase the force.
All of the above
The easiest way to open a heavy door is by applying the force
At the edge of the door far from the hinges
The diagram shows the Forces acts on a skydiver. The skydiver affected by drag and weight. The diagram shows the direction of motion and direction of forces as well. At which point the skydiver move with a constant speed?
At the middle
Suppose a rescue airplane drops a relief package while it is moving with a constant horizontal speed at an elevated height. Assuming that air resistance is negligible, where will the relief package land relative to the plane?,
B: directly below the plane C: below the plane and ahead of it
A bug is hit by a car. Which one experiences the greater force?
Both will experience a same force
Projectile motion has two components, horizontal (x) and vertical (y). The vertical motion has:
Constant acceleration
Projectile motion has two components, horizontal (x) and vertical (y). The horizontal motion has:
Constant velocity
A car is going around a banked curve at a high rate of speed. For the car not to skid, in which direction does the frictional force act?,
Directly towards the center of the curve
You weigh an object by hanging it from a rope which works by reading the amount of tension. You do this on a moving elevator. Under which of the following circumstances would you expect the scale to read more than the actual weight.
Elevator moving downward with constant acceleration.
Without air resistance, a projectile fired horizontally at 25,000 mph from atop of a mountain would
Escape from the Earth
F = m a
F = 2 kg x 10 ms-2 mass x 4 ms-2 = 2 kg x 10 ms-2 mass = 20/4 = 5 kg
Which scientists drop things from the Leaning Tower of Pisa
Galileo
Who discovered Newton's First Law of Motion?
Galileo
Without air resistance, a projectile fired horizontally at 17,000 mph (8 km/s) from atop of a mountain would
Go into a circular orbit around the Earth.
What Force is always at work here on Earth?
Gravitational
The normal force
Is always perpendicular to the surface.
The fundamental (base) unit of work and energy is
Joule
The SI unit use to measure force is
N
At the instant a ball is thrown horizontally with a large force, an identical ball is dropped from the same height. Which ball hits the ground first? (an example is tennis ball race)
Neither, both hit the ground at the same time.
These two ice skaters have just pushed off against one another. One skater has twice the mass as the other. Which one will experience the greater momentum? (remember: momentum is conserved)
Neither, they both have the same momentum
A magician pulls a tablecloth out from under dishes and glasses on a table without disturbing them. This scenario can be explain using
Newton's 1st Law
What is the Unit for Torque
Nm
The diagram shows the Forces acts on a skydiver. The skydiver affected by drag and weight. The diagram shows the direction of motion and direction of forces as well. No, the sky driver will reach a terminal velocity because of his weight balance with air friction. Does a skydiver continue to accelerate?
No, the sky driver will reach a terminal velocity because of his weight balance with air friction.
What type of Forces are acting on the pictures shown here(hint/parachute)
Non contact: Gravitational Force and Contact force: Air Resistance
You stand on a scale that rests on the floor of an elevator that is accelerating upward. What is the relationship between the force due to gravity (mg) and the normal force (N) exerted by the scale?
Normal force is larger than the weight
You are pushing a crate rightwards with a mass of 10 kg with a force of 150 N. The surface is rough;and the frictional force has a magnitude of 100 N. The net force on the mass (Hint draw a diagram and mark the forces on the diagram)
Rightwards, 50 N
A figure skater spins with her arms extended. When she pulls in her arms she spins faster because
She has decreased her rotational inertia
Low and high tides occur due to the following reasons
The gravitational pull from the moon and the earth rotation around it's own axis.
These two ice skaters have just pushed off against one another. One skater has twice the mass as the other. Which one will experience the greater speed? (remember: momentum is conserved)
The lighter skater
No air friction, Which of these three balls would hit the floor first if all three left the tabletop at the same time?
They would all hit at the same time.
A bus hits a bug and the bug splatters on the windshield,which force is greater?,
They're the same
An astronaut is taking a spacewalk when his tether breaks. He has a big drill. How can he get back to the spaceship?
Turn his back to the ship and throw the drill forward( oppersite to the rocket)
Projectile motion is a
Two Dimentional Motion
Which of the following statements are true of both weight and mass?
Weight is a force, mass is a measure of inertia.
A rifle sight is set so that you will hit a target at 200m. If, instead, you wish to hit a target closer than 200m, should you aim high or low (rifle speed is fixed)?
You should aim high or it's low complimentary angle since the bullet will drop due to the effect of gravity
Which of the two trajectories shown will result in a long time for the ball to reach home plate? (baseball)
a)The higher trajectory takes longer. The time of flight is determined by the initial vertical velocity component which also determines the maximum height reached
Which free-throw trajectory has the greatest chance of success?
a)The upper path is more likely to go thru if the ball player has the same control for either path.
What does this formula measure?
angular momentum
Which path correctly indicates the motion of the pendulum bob when it is cut at the instant it is at the top of its swing?
b
With the presence of gravitational acceleration down.Which path correctly indicates the motion of the pendulum bob after the string is cut when the pendulum is at the bottom of its swing?
c
Projectile motion is characterized by
constant velocity in the x-direction and constant acceleration in the y-direction
Suppose a rescue airplane drops a relief package while it is moving with a constant horizontal speed at an elevated height. Assuming that air resistance is negligible, where will the relief package land relative to the plane?
directly below the plane
Which of the following correctly states Newton's third law of motion? Forces occur in matched pairs that are
equal in magnitude and opposite in direction.
Motions need an unbalanced net force to maintain its motion
false
A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms
her moment of inertia increases and her angular speed decreases.
What is Newton's First Law known as? The Law of
inertia
Galileo said that a moving object with nothing pushing or pulling on it will always
keep moving at the same velocity.
Kinetic energy is energy that an object possesses because of its
motion
You put your notebook on the front seat of your car. When your car stops,the notebook slides off forward. Why?,
no force is pushing it, so the book will continue the motion.
When a bullet is fired from a gun, the bullet keeps moving after it leaves the gun barrel because
no force stops it
In projectile motion with no air resistance, the horizontal component of the velocity at the top of the trajectory is
non-zero, and equal to the initial horizontal component of the velocity
In projectile motion in real life with air around the motion, the horizontal component of the velocity at the top of the trajectory is
non-zero, and greater than or less than the initial horizontal component of the velocity depending on the wind velocity.
In projectile motion the velocity at the top of the trajectory is
non-zero, since the horizontal (x) component of the velocity has remained constant.
According to Newton's second law of motion, acceleration is proportional to force. That means a larger force
produces a larger acceleration.
If the forces on an object are balanced, the object will
remain at rest if initially at rest.
The moment of inertia:
resistance to a change in rotational motion
When you walk on a rough surface the force on the foot created by the
rough surface
What two factors do you use to describe a force?
strength and direction
The recoil or 'kick' of a gun that is firing a bullet is a force exerted on the gun by
the bullet
A book is sitting on a desktop. Identify newton's 3rd law partner of the weight of the book.
the force created by the book on the earth
A book is sitting on a desktop. Identify the 3rd law partner of the weight of the book. Note that weight is the force created by the earth on the book
the force of the book on the earth
When you walk on the ground, your foot push against the ground and the ground pushes back on you. The force that makes you walk is exerted by
the ground.
If an astronaut takes an object to the moon. Which of the following statements is true?
the weight will change but the mass will be the same.
Forces that are not cancel each other are called __________ forces.
unbalanced
Force is a
vector quantity
An ice skater glides across a frozen pond at a constant velocity. What is the net force acting on the skater?
zero
In projectile motion the vertical velocity at the top of the trajectory is
zero
Two people pull on a rope in a tug-of-war. Each pull with 400 N of force. What is the net tension in the rope
zero
In projectile motion with the presence of air the vertical component of the velocity at the top of the trajectory is
zero, otherwise the object can not fall back.
