All categories

2 years ago

A force of 77 N is used to move a desk 1.5 m. How much work was done?

Physics

1 answer:

Sloan [31]2 years ago

3 0

Answer:

As we know,

work = 77 N × 1.5m

therefore 115.5 J work was done

You might be interested in

Complete the statement below with all that apply.

lianna [129]

Acceleration is the rate of change of velocity, and velocity is the change in displacement over the change in time so the answer would be A.

3 0

3 years ago

Read 2 more answers

What is the radius of a nucleus of an atom?

Advocard [28]

Answer:

i think its 1-10 ´ 10-15 m

Explanation:

4 0

3 years ago

Read 2 more answers

A long copper rod of diameter 2.0 cm is initially at a uniform temperature of 100°C. It is now exposed to an air stream at 20°C

Lisa [10]

Answer:

t = 4.0 min

Explanation:

given data:

diameter of rod = 2 cm

T_1 = 100 degree celcius

Air stream temperature = 20 degree celcius

heat transfer coefficient = 200 W/m2. K

WE KNOW THAT

copper thermal conductivity = k = 401 W/m °C

copper specific heat Cp = 385 J/kg.°C

density of copper = 8933 kg/m3

charateristic length is given as Lc

$Lc = \frac{V}{A_s}$

$Lc = \frac{\frac{\pi D^2}{4} L}{\pi DL}$

$Lc = \frac{D}{4}$

$Lc = \frac{0.02}{6} = 0.005 m$

Biot number is given as $Bi = \frac{hLc}{k}$

$Bi = \frac{200*0.005}{401}$

Bi = 0.0025

As Bi is greater than 0.1 therefore lumped system analysis is applicable

so we have

$\frac{T(t) - T_∞}{Ti - T_∞} = e^{-bt}$ ............1

where b is given as

$b = \frac{ hA}{\rho Cp V}$

$b = \frac{ h}{\rho Cp Lc}$

$b = \frac{200}{8933*385*0.005}$

b = 0.01163 s^{-1}

putting value in equation 1

$\frac{25-20}{100-20} = e^{-0.01163t}$

solving for t we get

t = 4.0 min

6 0

3 years ago

(PLEASE HELP FAST 20 POINTS)

Lera25 [3.4K]

Everything we see or do in everyday life that involves electricity in any way is the result of electrons moving from one place to another, or from one object to another. <em> (last choice)</em>

4 0

3 years ago

According to Newton's law of motion, when we shake a mango tree, mangoes fall down explain.

Reptile [31]

When we shake a mango tree, the mangoes fall down. It is because when we shake the tree, the mango tend to be rest due to inertia where as the branches are in motion. That is why the mangoes tend to be at rest due to inertia where as the branches are in the motion.

8 0

3 years ago