A stone is thrown vertically upwards and the height x ft reached by the stone in t seconds is given by x = 80 t - 16t2 The stone reaches the maximum height in
2 s
2.5 s
3 s
1.5 s
The maximum value of is
1
e
D.
A stone is thrown vertically upwards from the top of a tower 64 m high according to the law s = 48t - 16t2. The greatest height attained by the stone above ground is
36 m
32 m
100 m
64 m
A wire of length 20 cm is bent in the form of a sector of a circle. The maximum area that can be enclosed by the wire is
20 sq cm
25 sq cm
10 sq cm
30 sq cm
The condition for the line y = mx + c to be a normal to the parabola y2 = 4ax is
c = - 2am - am3
c = 2am + am3