The correct options are specified with their questions numbers
1 = B , 2 = C , 3 = B , 4 = A , 6 = C , 7 = A , 8 = A , 9 = D , 10 = A , 11 = A
Physics full notes of class 11 ch2 McQs section end.
See questions in book.
Question 1 Answer: Consider two vectors ‘A’ (With arrow head) and ‘B’ (With arrow head) such that the magnitude of ‘A’ is greater than ‘B’ as shown in the figure.
Now if the two vectors are acting along the same line and same direction , then their resultant is given by,
R = A + B
If the two vectors are acting along the same line in opposite direction , then their resultant is given by ,
R = A – B
Thus the range of the possible values of the resultant of the two vectors A and B varies from A+B to A-B.
Question 2 Answer: The minimum number of unequal vectors to result into a null vector must be three. If we add three vectors of unequal magnitude in such a way that they forms the sides of a triangle , then their resultant must be zero.
(Draw a traingle)
In the given figure three vectors A, B and C are added according to head to tail rule and they form the sides of a triangle. Now for getting their resultant, we will combine the tail of A with the head of C which already coincides eash other . Thsu we get a null vector or zero vector as a resultant . So we have R = A+B+C = 0.
Question 3 Answer will you find at the end of the last chapter.
Question 4 Answer: We know that objects with a high center of gravity are likely to be unstable. For this reson the bases of the cranes are made low and heavy , so that center of gravity remains low.
The torque produced by a heavy load lifted by a crane is counterbalanced by its heavy load and large moment arm. Thus the cranes do not topple when they carry heavy loads.
Question 5 Answer: We know that the torque depends upon the moment arm and applied force. Mathematically we have,
T = r x F ———- 1
As we have given that the gravitational force acting on a setellite is directed is directed towards the center of the earth . As for central force , the moment arm is zero i-r r = 0 ,So eq 1 T = r x F = 0
T = 0 ————- 2
Eq 2 shows tha tthe torque produced by gravitational force acting on a satellite is zero.
Question 6 Answer : We know that the magnitude of torque depends upon the moment arm and applied force,
T = r x F ———1
Equation 1 shows that to produce grater torque with a less applied force , the value of moment arm ‘ r ‘ must be taken as larger . Due to greater torque we can turn the heavy trucks and buses easily. That is why heavy trucks and bsues have large steering wheels to produce greater torque and to make the drive more easy.
Physics full notes of class 11 ch2 short questions end.