You set your stationary bike on a high 80 N friction like resistive force and cycle for 30 min at speed of 8 m/s. Your body is 10% efficient at converting chemical energy in your body into mechanical work. What is your internal chemical energy change? How long must you bike to convert 300000 J of chemical potential while staying at this speed?
I converted 30 min to 1800 sec
don't know what to do from there
Why no one answer me
To find your internal chemical energy change, you need to calculate the work done against the frictional resistive force during the 30 minutes of cycling.
First, let's calculate the work done against the frictional resistive force:
Work done = Force x Distance
= Frictional resistive force x Distance
To find the distance travelled, you need to calculate the average speed:
Average speed = Total distance / Total time
Since the speed of 8 m/s is constant during the 30 minutes, the total distance covered would be:
Total distance = Speed x Time
= 8 m/s x 1800 sec
Now, let's calculate the work done:
Work done = Frictional resistive force x Total distance
= 80 N x (8 m/s x 1800 sec)
To find the internal chemical energy change, we need to account for the efficiency of converting chemical energy into mechanical work. The efficiency is given as 10%, which means only 10% of the chemical energy is converted into mechanical work.
Internal chemical energy change = Work done / Efficiency
= (80 N x (8 m/s x 1800 sec)) / 0.1
Now, let's calculate the internal chemical energy change using the given values.
Next, to determine how long you must bike to convert 300,000 J of chemical potential energy while staying at the same speed, we need to calculate the work done and the time needed.
First, let's calculate the work done required:
Work done = Chemical potential energy change
Work done = 300,000 J
Now we can use the work-energy principle to find the time required to convert this amount of chemical potential energy:
Work done = Force x Distance
Since the resistive force remains the same, we can rearrange the equation to find the distance:
Distance = Work done / Force
Now, we can find the time using the equation:
Time = Distance / Speed
Given that the resistive force is 80 N and the speed is 8 m/s, we can substitute the values into the equation to find the distance covered:
Distance = (300,000 J) / (80 N)
With the distance, we can calculate the time required:
Time = Distance / Speed
Now you can substitute the calculated distance and the given speed to find the time required to convert 300,000 J of chemical potential energy while maintaining the same speed.