If a machine decreases the distance an object moves, it must also . increase the object's acceleration
decrease the force used to move the object
decrease the object's mass
increase the force used to move the object

The energy released by a chemical reaction can be measured using a calorimeter. when barium hydroxide octahydrate crystals are reacted with dry ammonium chloride inside of a coffee cup calorimeter, the temperature of the 18.00 g of water in the calorimeter decreases from 30.0°c to 8.0°c. the equation for calculating energy absorbed or released by a reaction is: where q is the energy released or absorbed, m is the mass of water in the calorimeter, cp is the specific heat of water, and δt is the observed temperature change. if the specific heat of liquid water is 4.19 j/g·°c, how much energy was absorbed by the reaction?

Work out sian speed for the first 30 minutes of her journey. give your answer in km/h.

Idon’t quite understand this problem