How to find the mass, knowing the speed

The ability to determine the mass of a moving body can be useful not only at school physics lessons, but also in everyday life. Suppose you want to raise the excavator vehicle, the weight of which is unknown, wherein a known speed at which the car is raised.

Instruction

Use the formula F=ma, where F is the force (measured in Newtons), m is the mass of the vehicle, a is the acceleration. To find mass, use the rule to find unknown multiplier: "to find an unknown multiplier, we need work divided by the known multiplier." Work: m=F/a.

Now replace the known value of acceleration – speed (V). Use the formula a=V/t, where t is the time in which the rise of the machine. If the time is given in seconds, speed in meters per minute, that may equalize the values. Put time in minutes, speed in meters per second.

In the original formula m=F/a substitute the resulting value of acceleration. Work: m=F/V/t. Use the rule of division by a fraction: "When you divide by a fraction, its denominator goes up, the numerator down." Hence: m=Ft/V.

Now, to find mass, substitute into the formula m=Ft/V known values. For example: F=50 N (Newtons), t=10 s (seconds), V=1 m/s (meters per second). Work: m=50 N x 10 s / 1 m/s, m=500 kilograms.

Is the advice useful?