Achemical reaction’s main identifying sign is bubbles. true or false?

TRUE

It is true that bubbles is a sign of a chemical reaction. The formation of bubbles when an antacid tablet makes contact with water is an example of a chemical reaction where the mixture becomes saturated with gas.

Moreover, chemical property cannot be determined by merely viewing or touching the substance, for the substance composition must changed. This means that the substance molecular structure must be affected or bonds are broken to form new ones to indicate chemical change. Other indicators of chemical change includes change in temperature, color, odor and formation of precipitate.

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards