Physics, 31.08.2019 16:30 ozieera

A200 kg crate is pulled along a level surface by an engine. the coefficient of friction between crate and surface is 0.4.
a. how much power must the engine deliver to move the crate at 5.0m/s.
b. how much work is done by the engine in 180s

Answers: 1

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Answers

Normal force = 200(9.81) = 1962 N
Friction force = 1962 * .4 = 784.8
power = force * distance / time = 784.8 * 5 = 3924 Watts

Watts = Joules / sec
3924 x 180 = 706,320 Joules

Answer from: kayleahrayne

a)Power = P = 3924 watts

b)Work = W = 706320 J

Explanation:

a)Mass of the block = m = 200 kg

Velocity = V = 5 m/s

Time = t = 180s

Coefficient of friction = µ = 0.4

Gravitational acceleration = g = 9.81 m/s^2

According to newton’s second law of motion:

F-f = 0

Where,

F = Normal force

f = Frictional force

so,

F = f = µmg = (0.4)(200)(9.81) = 784.8 N

We know that:

P = FV = (784)(5) = 3924 watts

b) We know that:

W = P × t = 3924 × 180 = 706320 J

Answer from: Quest

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

$_a^z\textrm{x}\rightarrow _{a-2}^{z-4}+_2^4\alpha$

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

$_a^z\textrm{x}+_{-1}^0\textrm{e}\rightarrow _{z-1}^a\textrm{y}$

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases $\gamma -radiations$ . this process does not change the mass number.

$_a^z\textrm{x}^*\rightarrow _a^z\textrm{x}+_0^0\gamma$

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as $\beta ^+$ -decay. in this the mass number remains same.

$_a^z\textrm{x}\rightarrow _{z-1}^a\textrm{y}+_{+1}^0e$

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.

Answer from: Quest

i think they are all correct

explanation:

they seem good

Check if answers are correcti will mark as the brainliest answer

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