The work done by the elephant to lift one log is the force multiplied by the height at which the log has been lifted:

And so, the total work done to lift the 7 logs is 7 times the work done to lift each log:
Basically the cheetah is running 31.5km/h faster than the gazelle. So to determone how long it will take to cover 9mm at that speed, you have to a lot of work. If you skip all of that work, the answer is 1.60m seconds
Answer:

Explanation:
1. Find the equation of eht maximal friction force:
The maximal friction force is given by the equation
, where μs is the static friction coefficient, m is the car´s mass and g is the gravitational force.
2. Replace values in the equation to find the answer:

