3 A baseball is thrown straight upward with a speed of 30 m/s. (a) How long will it rise? (b) How high will
it rise? (c) How long after it leaves the hand will it return to the starting point? (d) When will its speed be
16 m/s? Ans. (a) 3.1 s; (b) 46 m; (c) 6.1's; (d) 1.4 s and 4.7 s​

Answers

Step-by-step explanation:

a) Time to max. height = (v/g) = 30/9.8 = 3.06 secs.

b)  Height attained = (v^2/2g) = 30^2/19.6 = 45.92 metres.

c) (3.06 x 2) = 6.12 secs.

d) Time to 16m/sec = (v/g) = 16/9.8 = 1.633 secs. Add 3.06 secs. if you need it to be time from release and then dropping to 16m/sec.

percentage - 25%

probability - 0.25

we know,

total amount of students in class = 20

total boys = 10

total girls = 10

no of girls who wear glasses = 10/2 = 5

probability of choosing a girl with glasses is =

number of girls wearing glasses/total number of students in the class = 5/20

thus, percentage of selecting a girl wearing glasses will be

= 5/20 × 100

= 5 × 5

25%

therefore,

probability will be 0.25

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step-by-step explanation: