How to find weight, knowing speed

How to find weight, knowing speed

The ability to determine the mass of a moving body can be useful not only at school lessons of physics, but also in usual life. Let's assume, it is required to lift the excavator the car which mass is unknown, at the same time the speed with which the car will be lifted is known.

Instruction

1. Use a formula F=ma where F is force (it is measured in newtons), m is the mass of the car, an is acceleration. To find weight, apply the rule of finding of an unknown multiplier: "To find an unknown multiplier, it is necessary to divide the work into the known multiplier". It will turn out: m=F/a.

2. Now replace acceleration with the known size – the speed (V). Use a formula a=V/t where t is time for which the car will rise. If time is given in seconds, and speed in meters per minute, then balance sizes. Change or time in minutes, or speed in meters for about a second.

3. In an initial formula m=F/a substitute the received value of acceleration. It will turn out: m=F/V/t. Use the rule of division into fraction: "At division into usual fraction its denominator leaves upward, and numerator - down". From here: m=Ft/V.

4. Now, to find weight, substitute the known values in a formula m=Ft/V. For example: F=50 N (newtons), t=10 since (seconds), V=1 m / c (meters per second). It will turn out: m=50 H x 10 with / 1 m/s, m=500 of kilograms.

Author: «MirrorInfo» Dream Team


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