Question

In this problem "up" is taken to be positive. A ball thrown vertically upward with an initial velocity of 19.6 m/s, after 5 s has a velocity of 1) 19.6 m/s 2) -19.6 m/s 3) 29.4 m/s 4) -29.4 m/s . Please give a detailed answer.

Answer 1

Use newton's equation:

v=u+gt
v=19.6-9.8*5           (g is negative as it act downward)
=-29.4 m/s^2

Answer 2

Answer:

Explanation:initial velocity of ball is 19.6

time taken is 5 secs

now using equation : v=u+at  we get

19.6-50=-30.4

here i used a= -10  u can use -9.8

coz its upward so acceleration is always negative

using -9.8 answer is -29.4