Which of the following is not correct?
A If we drop a 10 lb iron ball and 1 lb aluminium ball from the top of a high platform inside a mine, then both will reach the floor at the same time.
B The gravitational force of attraction between the two bodies increases when their masses are increased and distance is reduced.
C We do not observe small objects moving towards each other because frictional force balances the gravitational pull.
D When a body is thrown up, the acceleration due to gravity at the topmost point is zero because velocity of the body is zero.
Shouldn't it be C
A block of mass 10 kg is suspended through two light spring balances as shown in figure. Then
A Both the scales will read 10 kg
B Both the scales will read 5 kg
C The upper scale will read 10 kg and the lower scale zero
D The reading may be anything but their sum will be 10 kg.
Raghu used excessive chemical fertilisers in his field while Raman found the soil of his field to be basic in nature. What should they add to their fields to improve the quality of the soil?
A Raghu : Organic matter Raman : Quick lime
B Raghu : Quick lime Raman : Organic matter
C Both should add quick lime.
D Both should add organic matter.
What are the adaptations for flight in birds?
(i) Hollow bones to reduce body mass.
(ii) Feathers covering their body.
(iii) A streamlined body with powerful tail.
(iv) Wings with powerful muscles.
A (i) only
B (i), (ii) and (iii) only
C (i), (ii) and (iv) only
D (i), (ii), (iii) and (iv)
The given picture shows foot of a bird. Which of the birds given below can have this type of foot?