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2 years ago

11

An object with a mass of 6 kg is dropped from a height of 80 m. Consider the air resistance to be zero and g to be 10 m/s². What

is the kinetic energy of the object when it has fallen 60 m?
A. 1,200 J
B. 3,000 J
C. 3,600 J
D. 4,800 J

1 answer:

max2010maxim [7]2 years ago

5 0

Answer:

STOP BEING PRESSED

Explanation:

ANSWER B

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Why do things become hot or cold?<br> Relate to Thermal Energy and The Law of Conservation of Energy

Mekhanik [1.2K]

<u>Answer:</u>

Things become hot and cold because of the transfer of energy.

<u>Explanation:</u>

The energy possessed by an object or system is called thermal energy and heat is the flow of this energy. While the law of conversation of energy states that energy is not destroyed or created, it just transfers from one object to another.

When a hot object is placed in normal conditions, it transfers heat to the environment until both are at the same temperature and heat transfers from the environment to the cold objects placed in normal conditions.

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2 years ago

If you walk 800m north, 600m east, and 200 meters south at a speed of 1m/s. What is your velocity?

ryzh [129]

Answer:

0.375 m/s north & 0.375 m/s east

Explanation:

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3 years ago

A car and a motorcycle start from rest at the same time on a straight track, but the motorcycle is 25.0 m behind the car. The ca

sergeinik [125]

Answer:

t = 8.45 sec

car distance d = 132.09 m

bike distance d = 157.08 m

Explanation:

GIVEN :

motorcycle is 25 m behind the car , therefore distance need to covered by bike to overtake car is 25+ d, when car reache distance d at time t

for car

by equation of motion

$d = ut + \frac{1}{2}at^2$

u = 0 starting from rest

$d = \frac{1}{2}at^2$

$t^2 = \frac{2d}{a}$

for bike

$d+25 = 0 + \frac{1}{2}*4.40t^2$

$t^2= \frac{d+25}{2.20}$

equating time of both

$\frac{2d}{a} = \frac{d+25}{2.20}$

solving for d we get

d = 132 m

therefore t is $= \sqrt{\frac{2d}{a}}$

$t = \sqrt{\frac{2*132}{3.70}}$

t = 8.45 sec

each travelled in time 8.45 sec as

for car

$d = \frac{1}{2}*3.70 *8.45^2$

d = 132.09 m

fro bike

$d = \frac{1}{2}*4.40 *8.45^2$

d = 157.08 m

7 0

2 years ago

A solar reflector is made using 31 identical triangular-shaped mirrors, each having sides . What is the total surface area of th

Stels [109]

Complete Question

Question 18 (3 points) Solve the problem. (3 points) A solar reflector is made using 31 identical triangular-shaped mirrors, each having sides 2.4m, 2. 3m, 1.5 m. What is the total surface area of the reflector?

A) 33 m2

B) 86 m2

C) 52 m2

D) 34 m2

Answer:

The value is $Area =2.78 \ m^2$

Explanation:

From the question we are told that

The sides are a = 2.4 m

b = 2.3 m

c = 1.5 m

Generally the semi perimeter is mathematically represented as

$s = \frac { a + b + c }{2 }$

=> $s = \frac { 2.4 + 2.3 + 1.5 }{2 }$

=> $s =3.1 \ m$

Generally the using Heron's formula we have that the surface are a is mathematically represented as

$Area = \sqrt{S (S - a) (S - b )(S - c ) }$

=> $Area = \sqrt{3.1 (3.1 - 2.4) (3.1 - 2.3 )(3.1 - 1.5 ) }$

=> $Area =2.78 \ m^2$

6 0

2 years ago

Can someone help me in this one :)

djyliett [7]

I believe it is “runs on parallel circuits”! my bad if incorrect

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2 years ago