Answer: ![-\frac{1}{2}\times \frac{d[Br^.]}{dt}=+\frac{d[Br_2]}{dt}](https://tex.z-dn.net/?f=-%5Cfrac%7B1%7D%7B2%7D%5Ctimes%20%5Cfrac%7Bd%5BBr%5E.%5D%7D%7Bdt%7D%3D%2B%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D)
Explanation:
Rate of a reaction is defined as the rate of change of concentration per unit time.
Thus for reaction:

The rate in terms of reactants is given as negative as the concentration of reactants is decreasing with time whereas the rate in terms of products is given as positive as the concentration of products is increasing with time.
![Rate=-\frac{d[Br^.]}{2dt}](https://tex.z-dn.net/?f=Rate%3D-%5Cfrac%7Bd%5BBr%5E.%5D%7D%7B2dt%7D)
or ![Rate=+\frac{d[Br_2]}{dt}](https://tex.z-dn.net/?f=Rate%3D%2B%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D)
Thus ![-\frac{d[Br^.]}{2dt}=+\frac{d[Br_2]}{dt}](https://tex.z-dn.net/?f=-%5Cfrac%7Bd%5BBr%5E.%5D%7D%7B2dt%7D%3D%2B%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D)
Answer:
A. W = 6875.0 J.
B. W = -14264.6 J.
Explanation:
A. The work done by the rider can be calculated by using the following equation:

Where:
: is the force done by the rider = 25 N
d: is the distance = 275 m
θ: is the angle between the applied force and the distance
Since the applied force is in the same direction of the motion, the angle is zero.

Hence, the rider does a work of 6875.0 J on the bike.
B. The work done by the force of gravity on the bike is the following:
The force of gravity is given by the weight of the bike.
And the angle between the force of gravity and the direction of motion is 180°.
The minus sign is because the force of gravity is in the opposite direction to the motion direction.
Therefore, the magnitude of the work done by the force of gravity on the bike is 14264.6 J.
I hope it helps you!
Answer:
oh that looks hard but sorry im not good at math ether so sorry i couldnt help
Explanation: