Question

a string can hold up 12 kg without breaking. You tie the string to a 30kg object sitting on ice and use it to pull the object horizontally 22m. Calculate the minimum possible time to complete the task

Answer 1

Assume friction on ice is zero. All the force goes for acceleration.

Minimum possible time t is such that

22 m = (a/2)*t^2 with maximum possible a

Maximum accelaration a is

a = Fmax/m = (12*9.8 N)/30 kg
= 3.92 m/s^2

Now solve for t in the first equation, using that a value.

Answer 2

3.35