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the net external force on the 24-kg mower is stated to be 51 N. If the force of friction opposing the motion is 24 N, what force

-Dominant- [34]

Answer:

PART A)

External force will be 75 N

PART B)

distance moved will be 1.125 m

Explanation:

PART A)

Given that net force on the mower is

$F_{net} = 51 N$

now we also know that friction force due to ground is given as

$F_f = 24 N$

now we have

$F_{net} = F_{ext} - F_f$

$51 = F_{ext} - 24$

$F_{ext} = 75 N$

so external force will be 75 N

PART B)

deceleration due to friction when external force is removed from it

$a = \frac{F_f}{m}$

$a = \frac{24}{24} = 1 m/s^2$

now we can find the distance by kinematics

$v_f^2 - v_i^2 = 2 a d$

$0 - 1.5^2 = 2(-1)d$

$d = 1.125 m$

so the distance moved will be 1.125 m

6 0

3 years ago

"Compared to infrared radiation, does ultraviolet radiation have longer or shorter wavelengths? Does ultraviolet radiation have

balu736 [363]

Answer:Ultraviolet radiation has shorter wavelengths and higher energy than infrared radiation.

Explanation: Electromagnetic radiation radiations which have both electrical and magnetic properties,they can be transmitted through space or through a medium.

It includes Gamma radiation, infra-red, visible light, Ultraviolet radiation etc they occur with different wavelength, the lower the wavelength the higher the Energy dissipated per photon. According to their order of decreasing wavelength and increased energy they are classified as follows.

RADIO WAVE, MICRO WAVE, INFRA-RED, VISIBLE LIGHT, ULTRAVIOLET RAY, X-RAY, GAMMA RAYS.

5 0

3 years ago

Science is the human endeavor to understand the natural world true or flase

hjlf

True yes TRUE
Science may also be defined as the study of surroundings

4 0

3 years ago

In an electric furnace used for refining steel, the temperature is monitored by measuring the radiant power emitted through a sm

stiks02 [169]

Answer: 3.7×10¹²watts

Explanation:

Radiation is one of the mode of heat transfer and modes differs from each other based on their medium of heat transfer. Radiation is a process of transferring heat energy from one point to another without heating the intervening medium (no material medium is required).

According to Stefan's law of radiation, the rate of emission of radiant energy is directly proportional to the fourth power of its absolute temperature.

Mathematically, R = eAT⁴

e is constant of proportionality called emissivity. Emissivity varies depending on the type of body being considered.

For the question, we are considering black body and emissivity of black body is 1 being a perfect body.

A is the area of the body

T is the absolute temperature

e = 1

A = 0.5cm²

T = 1650°C

Rate of radiation = 1×0.5×1650⁴

= 3.7×10¹²watts.

The hole will therefore radiate 3.7×10¹²watts

3 0

3 years ago

Two small identical conducting spheres are placed with their centers 0.41 m apart. One is given a charge of 12 ✕ 10−9 C, the oth

nataly862011 [7]

(a) $-1.48\cdot 10^{-5}N$

The electrostatic force exerted between the two sphere is given by:

$F=k\frac{q_1 q_2}{r^2}$

where

k is the Coulomb's constant

q1, q2 are the charges on the two spheres

r is the separation between the centres of the two spheres

In this problem,

$q_1 = 12\cdot 10^{-9} C\\q_2 = -23\cdot 10^{-9} C\\r = 0.41 m$

Substituting these values into the equation, we find the force

$F=(9\cdot 10^9 Nm^2 C^{-2} )\frac{(12\cdot 10^{-9}C)(-23\cdot 10^{-9} C)}{(0.41 m)^2}=-1.48\cdot 10^{-5}N$

And the negative sign means the force is attractive, since the two spheres have charges of opposite sign.

(b) $+1.62\cdot 10^{-6}N$

The total net charge over the two sphere is:

$Q=q_1 +q_2 = 12\cdot 10^{-9}C+(-23\cdot 10^{-9}C)=-11\cdot 10^{-9} C$

When the two spheres are connected, the charge distribute equally over the two spheres (since they are identical, they have same capacitance), so each sphere will have a charge of

$q=\frac{Q}{2}=\frac{-11\cdot 10^{-9}C}{2}=-5.5\cdot 10^{-9}C$

So the electrostatic force between the two spheres will now be

$F=k\frac{q^2}{r^2}$

And substituting numbers, we find

$F=(9\cdot 10^9 Nm^2 C^{-2} )\frac{(-5.5\cdot 10^{-9} C)^2}{(0.41 m)^2}=+1.62\cdot 10^{-6}N$

and the positive sign means the force is repulsive, since the two spheres have same sign charges.

7 0

3 years ago