Question

1. a) What is the work done when a box weighing 10N is lifted up onto a shelf 2 m above the floor? b) If we consider the acceleration due to gravity to be 10ms?² and the same box (weighing 10N) moves at 10ms?¹ how much kinetic energy is used? c) How much potential energy does the box have when it is on the shelf? d) Thinking about the conservation of energy, if a block of mass 20kg falls off a shelf that is 3m above the ground what is the velocity of the box just before it it's the ground? 2. A person with a mass of 70kg runs up some stairs that are 25 m high in 12 seconds. How much energy was the person producing in this run? 3. A box of 20 kg is resting on a slope as shown in the diagram. 30° a) Label all the forces acting on the box. b) Calculate the normal reaction force the slope exerts on the box. c) Calculate the component of the weight parallel to the slope. d) If the box accelerates down the slope at 10ms?² what is the magnitude of the friction? 4. a) Two children are sat on a see-saw. Sheila is 35 kg and is sat at the end, 2.0m from the pivot. Michael is 45 kg and sits on the opposite side of the pivot. Calculate at what distance (x) must he sit to balance the see-saw.

          1.
a) What is the work done when a box weighing 10N is lifted up onto a shelf 2 m above the floor?
b) If we consider the acceleration due to gravity to be 10ms?² and the same box (weighing 10N) moves at 10ms?¹ how much kinetic energy is used?
c) How much potential energy does the box have when it is on the shelf?
d) Thinking about the conservation of energy, if a block of mass 20kg falls off a shelf that is 3m above the ground what is the velocity of the box just before it it's the ground?
2. A person with a mass of 70kg runs up some stairs that are 25 m high in 12 seconds. How much energy was the person producing in this run?
3. A box of 20 kg is resting on a slope as shown in the diagram.
30°
a) Label all the forces acting on the box.
b) Calculate the normal reaction force the slope exerts on the box.
c) Calculate the component of the weight parallel to the slope.
d) If the box accelerates down the slope at 10ms?² what is the magnitude of the friction?
4.
a) Two children are sat on a see-saw. Sheila is 35 kg and is sat at the end, 2.0m from the pivot. Michael is 45 kg and sits on the opposite side of the pivot. Calculate at what distance (x) must he sit to balance the see-saw.

1.
a) What is the work done when a box weighing 10N is lifted up onto a shelf 2 m above the floor?
b) If we consider the acceleration due to gravity to be 10ms?² and the same box (weighing 10N) moves at 10ms?¹ how much kinetic energy is used?
c) How much potential energy does the box have when it is on the shelf?
d) Thinking about the conservation of energy, if a block of mass 20kg falls off a shelf that is 3m above the ground what is the velocity of the box just before it it's the ground?
2. A person with a mass of 70kg runs up some stairs that are 25 m high in 12 seconds. How much energy was the person producing in this run?
3. A box of 20 kg is resting on a slope as shown in the diagram.
30°
a) Label all the forces acting on the box.
b) Calculate the normal reaction force the slope exerts on the box.
c) Calculate the component of the weight parallel to the slope.
d) If the box accelerates down the slope at 10ms?² what is the magnitude of the friction?
4.
a) Two children are sat on a see-saw. Sheila is 35 kg and is sat at the end, 2.0m from the pivot. Michael is 45 kg and sits on the opposite side of the pivot. Calculate at what distance (x) must he sit to balance the see-saw.

Added by David P.

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