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KE = 1/2 my2
1. You throw a ball with a mass of 2.1 kg. The ball leaves your hand at 30m/s.
energy. Calculate it.
The ball has
2. There is a bell at the top of a tower that is 50 m high. The bell weighs 190N.
The bell has
energy. Calculate it.
3. At what height is an object that has a mass of 56 kg if its gravitational poten-
tial energy is 9800 J?
4. There is a blender at the cabinet that is 5 m high. THe blender weighs 50N.
The blender has
energy. Calculate it.​


Sagot :

Problem 1:

The ball has kinetic energy.

Given:

m = 2.1 kg

v = 30 m/s

Required:

KE

Equation:

[tex]KE = \dfrac{1}{2}mv^{2}[/tex]

Solution:

[tex]KE = \dfrac{1}{2}mv^{2}[/tex]

[tex]KE = \dfrac{1}{2}(\text{2.1 kg})(\text{30 m/s})^{2}[/tex]

[tex]\boxed{KE = \text{945 J}}[/tex]

Answer:

945 J

---------------------------------------------------------

Problem 2:

The bell has potential energy.

Given:

w = 190 N

h = 50 m

Required:

PE

Equation:

PE = wh

Solution:

PE = wh

PE = (190 N)(50 m)

[tex]\boxed{PE = \text{9,500 J}}[/tex]

Answer:

9,500 J

---------------------------------------------------------

Problem 3:

Given:

PE = 9,800 J

g = 9.8 m/s²

m = 56 kg

Required:

h

Equation:

[tex]h = \dfrac{PE}{mg}[/tex]

Solution:

[tex]h = \dfrac{PE}{mg}[/tex]

[tex]h = \dfrac{\text{9,800 J}}{(\text{56 kg})(\text{9.8 m/}\text{s}^{2})}[/tex]

[tex]\boxed{h = \text{17.86 m}}[/tex]

Answer:

17.86 m

---------------------------------------------------------

Problem 4:

The blender has potential energy.

Given:

w = 50 N

h = 5 m

Required:

PE

Equation:

PE = wh

Solution:

PE = wh

PE = (50 N)(5 m)

[tex]\boxed{PE = \text{250 J}}[/tex]

Answer:

250 J

[tex]\\[/tex]

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