A hammer has a mass of 1.7kg. How much does it weigh?

17 N

Explanation:

Weight is a force. The equation to calculate a force is:

where a is the acceleration of the object. On an object simply existing, the force of gravity adds an acceleration of 9.8m/s², or approximately 10m/s². So, to calculate the force of weight, we simply multiply the mass by 10 for that reason:

Forces are measured in Newtons (N) so the answer is 17 N.

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me