Kinetic and Potential Energy
Is potential energy a vector or a scalar, what about kinetic energy
Both are scalars
What are the units of k?
N/m
Is there friction in an isolated system?
No
What are the units of momentum and impulse
kg*m/s or N*s
If an object initially at rest spontaneously explodes into two pieces, will the pieces travel in the same or in opposite directions?
opposite directions
If a 1012kg car has a velocity of 10m/s, what is the Kinetic Energy?
50600 J
A 25 kg box is lifted straight upward 2.0 m in 1.5 s.
Find the average power output.
326.7 Watts
Assuming no air resistance, if a box is dropped from rest with a Potential Energy of 15 J what is the Kinetic Energy just before the box hits the ground?
15 J
A man has momentum of 30kgm/s, if he weighs 980N, what is his velocity?
0.3m/s
If a dart is thrown at a box and sticks in the box, is kinetic energy conserved?
No, because it is an inelastic collision
If I did 200 J of work on a 60kg box that was initially at rest, what is the final velocity?
2.58m/s
What is the equation for Hooke's law, what about Spring potential energy?
Hooke's law F = -kx
Spring U = 1/2(k)(x)^2
54 J
what is the momentum of a 4kg box moving 12m/s in the negative x direction
-48 kg * m/s
A rubber ball is dropped from the same height onto concrete and onto a thick gym mat. In both cases, the ball rebounds to the same height, but it spends less time in contact with the concrete than with the mat. Which surface exerts the greater average force on the ball during contact?
The concrete
If there is a 32kg box that has a velocity of 21.4m/s at a height of 68m, what is the total mechanical energy of the box?
28652.16 J
If a box is held against a spring that is compressed by 0.3m. If the spring has a potential energy of 15.75 J, what is the spring constant?
350 N/m
A 48kg box is compressed 48cm up against a spring with constant k = 324 N/m. If the box is released from rest, what is the Kinetic energy just after the box looses contact with the spring?
37.32 J
A 0.25 kg puck moving right at 8.0 m/s rebounds left at 6.0 m/s. If contact time is 0.010 s, find the average force
-350 N
Is a rollar coaster of mass 200kg starts at rest at the top of a 300m hill, what is the momentum at the bottom of the hill? Assume no friction.
about 15,300 kg*m/s
If gravity did -15582 J of work on a 10kg box, and the final height of the box is 200m, what is the initial height of the box?
41m
What is the power output for a 60.0-kg woman who runs up a 3.00 m high flight of stairs in 3.50 s, starting from rest but having a final speed of 2.00 m/s?
538 Watts
If a 32kg box, starting from rest, is sliding down an incline with a coefficient of kinetic friction 0.34. If the incline is 30 degrees above the horizontal and the box starts at a height 30m, what is the speed at the bottom of the incline?
15.55m/s
If the initial momentum of an object was 12 kg*m/s and the impulse is also 12 N*s, and the final velocity is 6m/s, what is the mass of the object?
4kg
A box with mass 230g is traveling at 4m/s to the right, and another box with mass 790g is traveling to the left at 2m/s. If the boxes collide and stick together, what is the final velocity of box 1.
-0.65m/s