Select the correct answer. which category of materials does concrete belong to and why? a. it’s a synthetic polymer because it’s a product of a chemical reaction. b. it’s an alloy because it contains layers of different components. c. it’s a ceramic because it contains substances such as sand and clay. d. it’s a composite because it’s a mixture of cement, sand, and other granular pieces.

the device is called “ rocket engine”

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.