What is the term for an object used to observe the state of rest or motion?

Calculate the first and second velocities of the car with four washers attached to the pulley, using the formulas v1 = 0.25 m / t1 , and v2 = 0.25 m / (t2 – t1) where t1 and t2 are the average times the car took to reach the 0.25 and the 0.50 meter marks. record these velocities, to two decimal places, in table e.

Of is j/kg·k. if a 2.6 kg of isk to k,is ?

Am i correct on these two physics questions?