Question
The bicycle travels at a constant speed. Complete the sentences. Choose answers from the box. [3 marks] chemical frictional kinetic magnetic tension As the bicycle moves , work is done against __ forces. There is no change in the cyclist's __ store of energy. There is a decrease in the cyclist's __ store of energy.
Answer
4.2
(210 Votes)
Matilda
Master · Tutor for 5 years
Answer
"As the bicycle moves, work is done against (air resistance, friction, and gravity) forces. There is no change in the cyclist's (kinetic) store of energy. There is a decrease in the cyclist's (chemical) store of energy."
Explanation
## Step 1: Understand the sentence completion scenario presented. We are asked to fill in the blanks on three topics: work done against some force while the bicycle moves, the energy store that is not affected in the process, and the energy store that decreases. Let's approach each one.## Step 2: As the bicycle travels, work is done against certain forces. In the case of cycling, primarily, there are friction such as air resistance and ground friction, and the force of gravity (especially when going uphill).### Formula used here is: Firstly,
where W represents work, F the force applied, and d the distance. Also,
where F is force, m mass and a acceleration. Combining these 2, we can almost decipher which opposes a constant-speed motion.## Step 3: The next statement talks about no change in the cyclist's store of energy. Given the bike travels at constant speed, the kinetic energy of a body in motion remains constant as long as the speed is unchanging. ### Our concept here: Kinetic energy,
, remains constant as the velocity,
, stays constant.## Step 4: Finally, focusing on the statement about a decrease in the cyclist's energy store. To cycle, especially at a constant speed, the cyclist must use their stored chemical energy in the muscles. This gets lowered as it converts to kinetic energy (for cycling) and some loses as heat due to metabolism.