Aball is thrown at 25 m/s making an angle of 50° over a horizontal line. in which instant it velocity will make an 30° angle over a horizontal line?

0.68 sec

Explanation:

let the velocity be "v" when the angle is  30° .

Consider the motion along the horizontal direction

= initial velocity of ball along horizontal direction = 25 Cos50

= 16.07 m/s

= final velocity of ball along horizontal direction = v Cos30

we know that along the horizontal direction

=

v Cos30 = 16.07

v = 18.56 m/s

Consider the motion along the vertical direction

= initial velocity of ball along vertical direction = 25 Sin50

= 19.2 m/s

= final velocity of ball along vertical direction = v Sin30 = 25 Sin30 = 12.5 m/s

= acceleration = - 9.8 m/s²

= time taken

using the equation

12.5 = 19.2 + (- 9.8) t

t = 0.68 sec

another example of kinetic energy would be,

kinetic energy   >     moving energy

answer   >   letter choice (c),   a hammer falling off a table.

hope that !                                         : )

a displacement distance is size of displ