1. a=(v-v0)/t
a=14 m/s / 2s
a=7 m/s^2
2. <span>a=(v-v0)/t
</span>a=(30 m/s - 0 m/s) / 12 s
a=2.5 m/s^2
3. <span>a=(v-v0)/t
a=(37 m/s - 22 m/s) / 2 s
a= 7.5 m/s^2
4. </span><span>a=(v-v0)/t
a=(12 km/s - 0 km/s)/8 s
a=1.5 km/s^2
etc</span>
Answer:
A typical consumer microwave oven consumes 1,100 W AC and produces 700 W of microwave power, an efficiency of 64%.
We can solve the problem by using the first law of thermodynamics:
where
is the variation of internal energy of the system
Q is the heat absorbed by the system
W is the work done by the system
In this problem, the heat absorbed by the system is Q=+44 J, and the increase in internal energy is
. So we can rearrange the equation to calculate the work done:
and the work is positive, which means that it is done by the system on the surrounding.