If a body is traveling with constant speed , it means that it's distance is constantly increasing with time.

If it goes 5m in 3min , it will go 5m in next 3 min.

Average velocity is the total displacement divided by total time.

When the body travels 5m in 3 min and 25 m in next 3min , average velocity
=(25+5)/(3+3)
=30/6
=5m/min

8 0

3 years ago

The heating element of a coffeemaker operates at 120 V and carries a current of 2.00 A. Assuming that the water absorbs all of t

gogolik [260]

Answer:

$t=671.5s$ .

Explanation:

The heat needed will be provided by the power dissipated by the resistor. This power gives certain energy per unit time, so we multiply it by time to get the energy provided: $Q=Pt$ .

The equation of heat given mass, specific heat and temperature change is $Q=mC\Delta T$ , and the equation of power dissipated by a resistor is $P=Vi$ .

Putting all together:

$mC\Delta T=Vit$ .

Which means:

$t=\frac{mC\Delta T}{Vi}$ .

From 23.0°C to 100°C we have a $\Delta T=77^{\circ}C$ , which we won't need to put in Kelvin in this case since it is a variation, so for our values we have:

$t=\frac{(0.5kg)(4186J/kg^{\circ}C)(77^{\circ}C)}{(120V)(2A)}=671.5s$ .

5 0

3 years ago