Subject :NSO Class : Class 7
Read the given statements and select the correct answer.
Statement 1 : The distance x at which a car can be
stopped by applying brakes depends on the initial
velocity.
Statement 2 : Mass of the car has no role to play.
A Both statements 1 and 2 are true and statement 2
is the correct explanation of statement 1.
B Both statements 1 and 2 are true but statement 2
is not the correct explanation of statement 1.
C Statement 1 is true and statement 2 is false.
D Both statements 1 and 2 are false.
mass of the car has role to play due to momentum.
Ans 1:
Class : Class 8
C is the correct answer. Force is applied to stop the vehicle. The formulae of force is mass * acceleration. Acceleration is final velocity - initial velocity by time. F= M*{(v-u)/t} and its kinetically equation is F=M *[v square - u square/ 2 * distance]. Which ever formula for force has been taken MASS is important. So clearly MASS HAS A ROLE TO PLAY. hence the answer must be C
Ans 2:
Class : Class 8
c is the correct answer and solution is also given in favour of option c. but answer is b
Ans 3:
Class : Class 6
Though it looks like mass has no role to play in braking distance, actually coeff of friction (COF) between tyre and road surface has inverse relationship with braking distance. COF depends on normal force due to weight of vehicle and therefore indirectly mass plays a role on braking distance. The correct answer should be C
Ans 4:
Class : Class 5
Ans 5:
Class : Class 9
Apropos to the question the mass of the car has a role in the momentum of the car, as Momentum=mv ,therefore option 'C' should be the correct answer.