Answer:
10 km/h
Explanation:
Before calculating the average speed, we need to convert the time taken for the trip from minutes to hours. Since 1 hour cointains 60 minutes, we have:

Karen's average speed is given by:

where
d = 5 km is the distance covered
t = 0.5 h is the time taken for the trip
Substituting into the equation, we find

Answer:
8090.01 J
Explanation:
The formula for kinetic energy is
. We are given the mass and velocity, so plug what is given into the equation. 
Explanation:
a) photovoltaic cell is a semiconductor device and it converts light energy to electrical energy
b) burning of coal converts chemical energy to heat energy
c) rubbing of both hands against each other converts mechanical to heat energy
Answer:B
Explanation: pls give brainliest