An object with a mass of 1500 g (grams) acceleratates 10.0 m/s^2 when an unknown force is applied to it. what is the amount of the force?

Acatapult is tested by roman legionnaires. they tabulate the results in a papyrus and 2000 years later the archaeological team reads (distances translated into modern units): range = 0.4 km; angle of launch = π/5 rad; landing height = launch height. what is the initial velocity of launch of the boulders if air resistance is negligible?

An object weighs 40n in air, weighs 20n when submerged in water and 30n when submerged in a liquid of unknown density. what is the density of the liquid?

Does anyone know how to solve this problem? i really need . i made an attempt but i just cant get it. a metal rod is 25.000 cm long at 25.0 degrees celsius. when heated to 102.0 degrees celsius, it is 25.054 cm long. what is the coefficient of linear expansion for this metal.