4. A cinder block is sitting on a platform 20 m high. It weighs 79 N. The block has... energy.
Calculate it.
energy
5. There is a bell at the top of a tower that is 45 m high. The bell weighs 190 N. The bell has...
energy. Calculate it.
6. A roller coaster is at the top of a 72 m hill and weighs 966 N. The coaster (at this moment) has...
energy. Calculate it.
7. What is the kinetic energy of a 3-kilogram ball that is rolling at
meters per second?
8. Two objects were lifted by a machine. One object had a mass of 2 kilograms, and was lifted at a speed of
2 m/sec. The other had a mass of 4 kilograms and was lifted at a rate of 3 m/sec.
a. Which object had more kinetic energy while it was being lifted?
b. Which object had more potential energy when it was lifted to a distance of 10 meters? Show your
calculation.
Same type of answers for the previous question of mine.
Answers
Step-by-step explanation:
4. block has ..P.E (potential energy)..
height (h) = 20 m
weighy (W) = 79 N
P.E = mgh
W = mg
P.E = Wh
P.E = (79)*(20)
P.E = 1580 J
5. bell has ..P.E...
h = 45 m
W = 190 N
P.E = Wh
P.E = 190*45
P.E = 8550 J
6.roller coaster(at that moment) has ..P.E...
h = 72 m
W = 966 N
P.E = Wh
P.E = 966*72
P.E = 69552 J
7. mass (m) = 3 kg
velocity (v) = 1 m/s
K.E = 1/2 mv²
K.E = 1/2 (3)(1)²
K.E = 1/2(3)
K.E = 3/2 J
or K.E = 1.5 J
8. Object A;
m = 2 kg
v = 2 m/s
Object B
m = 4 kg
v = 3 m/s
a) K.E = ?
object A; K.E = 1/2mv²
K.E = 1/2(2)(2)²
K.E = 1/2(2)(4)
K.E = 1/2(8)
K.E = 4 J
object B; K.E = 1/2mv²
K.E = 1/2(4)(3)²
K.E = 1/2(3)(9)
K.E = 1/2(27)
K.E = 13.5 J
Hence, in object B kinetic energy is more
b) P.E = ?
h = 10m
object A; P.E = mgh
P.E = (2)(9.8)(10)
P.E = 196 J
object B; P.E = mgh
P.E = (4)(9.8)(10)
P.E = 392 J
Hence P.E of object B is more