Aviles, Vasquez, Brol and Corredor Flashcards
- What is the equation of kinetic energy? - (remember)
KE=1/2mv^2
- What is the equation for potential energy? - (remember)
PE=mgh
Ashok, whose mass is 43 kg, sits 1.8 m from a pivot at the center of a seesaw. Steve, whose mass is 52 kg, wants to seesaw with Ashok. How far from the center of the seesaw should Steve sit?
d2=1.5
What is the definition of gravitational motion?
The force of attraction that bodies exert on one another as a result of their mass.
What is the definition of rotational motion?
The motion of a point in a circular path, where the center point is fixed on the fixed axis of rotation.
What is the torque formula? - (remember)
T=rFsin0
A bicycle-chain wheel has a radius of 7.70 cm. If the chain exerts a 35.0-N force on the wheel in the clockwise direction, what torque is needed to keep the wheel from turning?
Torque of 2.6N
Suppose the radius of the larger pulley in problem 18 was increased to 6.0 cm. What is the mass of basket A now?
0.056kg
A bicyclist, of mass 65.0 kg, stands on the pedal of a bicycle. The crank, which is 0.170 m long, makes a 45.0° angle with the vertical, as shown in Figure 11. The crank is attached to the chain wheel, which has a radius of 9.70 cm. What force must the chain exert to keep the wheel from turning?
789N
If the sailor in Example Problem 2 pulls with the same force through the same
displacement but at an angle of 50.0°, how much work is done on the boat by the
rope?
4.92*10^3 J
Two people lift a heavy box a distance of 15 m. They use ropes, each of which
makes an angle of 15° with the vertical. Each person exerts a force of 225 N.
Calculate the work done by the ropes.
6.95*10^3 J
A rope is used to pull a metal box a distance of 15.0 m across the floor. The rope is held at an angle of 46.0° with the floor, and a force of 628 N is applied to the rope. How much work does the rope do on the box?
6.54*10^3 J
CHALLENGE A comet with a mass of 7.85×1011 kg strikes Earth at a speed of
25.0 km/s. Find the kinetic energy of the comet in joules, and compare the work that is done by Earth in stopping the comet to the 4.2×1015 J of energy that was released by the largest nuclear weapon ever exploded.
5.8x10^4
A Newton is equal to?
Kilogram-meter per second squared.
A boy is standing on an elevator which is traveling downward with a constant velocity of 30 meters per second. The boy throws a ball vertically upward with a velocity of 10 meters per second relative to the elevator. What is the velocity of the ball, MAGNITUDE AND DIRECTION, relative to the elevator shaft the instant the boy releases the ball?
20m/s
Work is equal to?
The dot product of force and displacement.
The work done by a friction force is?
Always negative.
As defined in physics, work is:
A scalar quantity
What is a reference level? - (remember)
The position where GPE is defined to be zero.
Two forces have magnitudes of 11 newtons and 5 newtons. The magnitude of their sum could NOT be equal to which of the following values?
5 newtons.
A boy throws a ball vertically upward with a velocity of 6 meters per second. How long does it take the ball to return to the boy’s hand?
1.2 seconds
Which is the rate at which energy is transformed? - (remember)
Power= w/t
Why is light pure not energy?
Light is not pure energy. While it is true that light has no mass, this fact does not imply that light is pure energy.
Why is mass conserved in chemical reactions?
Mass is conserved in chemical reactions. The fundamental conservation law of the universe is the conservation of mass-energy.
