Ablock is hung by a string from the inside roof of a van. when the can goes straight ahead at a speed of 28 m/s, the block hangs vertically down. but when the van maintains this same speed around an unbanked curve (r = 150m), the block swings toward the outside of the curve. the string makes an angle θ with the veritcal. find θ.

θ =28.07⁰

Explanation:

when van moves around an unbanked curve, horizontal component of normal force is equal to centripetal force

---(1)

There is no motion in vertical direction, so vertical component of normal force is balanced with weight of block i.e.

----(2)

divide (1) and (2)

v = 28 m/s

r = 150 m

g = 9.8m/

θ = 28.07⁰

the answer is a. hope this .

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.