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valentina_108 [34]
3 years ago
8

A 1.8 kg book had been dropped from the top of the football stadium. It's speed is 4.8 m/s when it is 2.9 meters above the groun

d what is its mechanical energy?
Physics
1 answer:
MrRissso [65]3 years ago
4 0

Answer:

72.936 Joule

Explanation:

Mechanical Energy = Potential Energy + Kinetic Energy

Kinetic Energy = (1/2) x m x V² = (1/2) x 1.8 x 4.8² = 20.736 J

Potential Energy = m x g x h = 1.8 x 10 x 2.9 = 52.2 J

Total Mechanical Energy = 20.736 + 52.2 = 72.936 Joule

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Why do we consider eyes, ears, and fingers as physical sensor​
seraphim [82]

Answer:

because

Explanation:

because we need eye to see if you don't have eyes how you regnise some one

if you have ears how can you know who's voice is who's

if don't have fingers how can you know what your are holding this is why they are called physical sensors

4 0
3 years ago
Read 2 more answers
Find the temperature
NNADVOKAT [17]

Answer:

-------1

Explanation:

beacuse that is what i know

8 0
2 years ago
How much energy (in Joules) is released when 12.0 g of water cools from 20.0 °C to 11.0 °C? This is a grade 10 question from the
KATRIN_1 [288]

Answer: - 452.088joule

Explanation:

Given the following :

Mass of water = 12g

Change in temperature(Dt) = (11 - 20)°C = - 9°C

Specific heats capacity of water(c) = 4.186j/g°C

Q = mcDt

Where Q = quantity of heat

Q = 12g × 4.186j/g°C × - 9°C

Q = - 452.088joule

7 0
3 years ago
A 50.0 kg child stands at the rim of a merry-go-round of radius 1.50 m, rotating with an angular speed of 3.00 rad/s. (a) what i
White raven [17]
Weight of the child m = 50 kg 
Radius of the merry -go-around r = 1.50 m
 Angular speed w = 3.00 rad/s
 (a)Child's centripetal acceleration will be a = w^2 x r = 3^2 x 1.50 => a = 9 x
1.5
 Centripetal Acceleration a = 13.5m/sec^2
 (b)The minimum force between her feet and the floor in circular path
 Circular Path length C = 2 x 3.14 x 1.50 => c = 3 x 3.14 => C = 9.424
 Time taken t = 2 x 3.14 / w => t = 6.28 / 3 => t = 2.09
 Calculating velocity v = distance / time = 9.424 / 2.09 m/s => v = 4.5 m/s
 Calculating force, from equation F x r = mv^2 => F = mv^2 / r => 50 x (4.5)^2

/ 1.5
 F = 50 x 3 x 4.5 => F = 150 x 4.5 => F = 675 N
 (c)Minimum coefficient of static friction u
 F = u x m x g => u = F / m x g => u = 675/ 50 x 9.81 => 1.376 
 u = 1.376
 Hence with the force and the friction coefficient she is likely to stay on merry-go-around.
8 0
3 years ago
A rock is suspended by a light string. When the rock is in air, the tension in the string is 51.9 N . When the rock is totally i
Luden [163]

Answer:

\rho _{liquid}=1995.07kg/m^{3}

Explanation:

When the rock is immersed in unknown liquid the forces that act on it are shown as under

1) Tension T by the string

2) Weight W of the rock

3) Force of buoyancy due to displaced liquid B

For equilibrium we have T_{3}+B = W_{rock}

T_{3}+\rho _{Liquid}V_{rock}g=W_{rock}.....(\alpha)

When the rock is suspended in air for equilibrium we have

T_{1}=W_{rock}....(\beta)

When the rock is suspended in water for equilibrium we have

T_{2} + \rho _{water}V_{rock}g=W_{rock}.....(\gamma)

Using the given values of tension and solving α,β,γ simultaneously for \rho _{Liquid} we get

W_{rock}=51.9N\\31.6+1000\times V_{rock}\times g=51.9N\\\\11.4+\rho _{liquid}V_{rock}g=51.9N\\\\

Solving for density of liquid we get

\rho _{liquid}=\frac{51.9-11.4}{51.9-31.6}\times 1000

\rho _{liquid}=1995.07kg/m^{3}

5 0
3 years ago
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