Question

When running on its 11.4 V battery, a laptop computer uses 8.3 W. The computer can run on battery power for 8.0 h before the battery is depleted.a)What is the current delivered by the battery to the computer?b)How much energy, in joules, is this battery capable of supplying?c)How high off the ground could a 75 kg person be raised using the energy from this battery?

Answer 1

Answer:

(a) Current i =0.7280 A

(b) Energy = 238993.922 j

(c) Height h = 325.161 m

Explanation:

We have given that voltage V = 11.4 Volt

Power P = 8.3 Watt

Time t = 8 hour

We know that 1 hour = 3600 sec

So 8 hour = 28800 sec

(a) We have to calculate current

We know that power = voltage ×current

Current $i=\frac{P}{V}=\frac{8.3}{11.4}=0.7280A$

(b) We have to calculate the energy

Resistance is given by $R=\frac{V}{i}=\frac{11.4}{0.7280}=15.657ohm$

We know that energy $E=i^2Rt=0.7280^2\times 15.657\times 28800=238993.922j$

(a) Energy required to lift the mass is given by mgh

So $mgh=238993.922j$

We have given mass m = 75 kg

So $75\times 9.8\times h=238993.922j$

h=325.161 m