A horse is working steadily, providing 750 WW of output power. How much food energy does the horse need to work for 1 hour, to the nearest MJMJ

2.7MJ

Explanation:

Power is expressed according to the formula

Power = work done/Time

The energy required is also known as the work done

Given

Power = 750Watts

Time = 1hr = 3600secs

Substitute the given values into the formula

750 = work done/3600

Work done = 750×3600

Work done = 2,700,000Joules

Convert to megajoules

Since

1MJ = 10^6Joules

x = 2.7×10^6Joules

Cross multiply

10^6x = 2.7×10^6

x = 2.7×10^6/10^6

x = 2.7

Hence the amount of energy absorber by the food in MJ is 2.7MJ

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s

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