Question

A crane takes 2.0 minutes to lift a 500 kg load to the top of a building that is 12 m high.
What is the useful power developed against gravity by the crane?

A)21W

B) 50 W

с) 500W

D)30 000 W

Answer 1

Answer:

Perfect questions for guys interested in maths..

2. The value of x + x(xx) when x = 2 is:

(a) 10, (b) 16, (c) 18, (d) 36, (e) 64

Solution:

x + x(xx)

Put the value of x = 2 in the above expression we get,

2 + 2(22)

= 2 + 2(2 × 2)

= 2 + 2(4)

= 2 + 8

= 10

Answer: (a)

Answer 2

Given - Time to lift the mass - 2 minutes

Mass of load - 500 kilogram

Height - 12 metre

Find - Power developed against gravity by crane.

Solution - Power can be calculated by the help of formula - P = W/t where p is power, w is work and t is time.

Calculating work done by the formula m*g*h, where m stands for mass, g for acceleration due to gravity and h for height.

W - 500*10*12 - 60000 J

Power - 60000/120

Power - 500 Watt

Thus, option (c) 500 W is the correct answer.