Answer:

Explanation:
d = Distance traveled = 40.8 km
s = Speed of jet = 340 m/s
Time is given by




The time taken to complete the journey is
.
The work done to push the refrigerator is 500 Nm.
Explanation:
Work done is the measure of force required to move any object from one point to another. So it is calculated as the product of force and displacement.
If the force increases the work done will increase and similarly, the increase in displacement increases the work done. So to push the refrigerator work should be done on the object and not by the object.
As the force is 100 N and the displacement is 5 m then, work done can be measured as
Work = Force × Displacement
Work = 100 × 5 = 500 Nm
So the work done to push the refrigerator is 500 Nm.
Velocity is speed plus the direction of the speed.
Answer: d)
Explanation: In order to justify the answer we have to consider that the energy of photons directely depent on the frequency so the energy is inverselly dependent of the wavelegth.
If both beams have the same power, this means Energy/time so the number of photons per second must be different. As consequence a) is wrong as b) since it is not posible since UV photon have more energy that IR photons. c) It is no necessary know the frequency since the wavelength is related in the form:
c=λν c is the speed of light, λ the wavelegth and ν the frequency.
d) Certainly will be more more IR photons than UV photons to get the same beam power.
Force is the product of mass and acceleration .
The question is ask to find acceleration.
But acceleration is the ratio of the force and the mass.
where 600kg is the mass and 7kN is the force
NB: kilo is 1000
now we have to multiply 7N by 1000
by doing so you will have 7000N
which is the force.
Now to find the acceleration: force/ mass
which is 7000/600
therefore the maximum acceleration is 11.667