A ball is thrown at 20.0 m s−1 at an angle 20.0° above the horizont

1.	A ball is thrown at 20.0 m s−1 at an angle 20.0° above the horizontal. Calculate the size of the ball’s instantaneous velocity at its highest point.(You may ignore air resistance. Give your answer in m s−1 to an appropriate number of significant figures.)
Answer» Given: A ball is thrown at 20.0 m s−1 at an ANGLE 20.0° above the horizontal. To find: Instantaneous VELOCITY of the ball at the highest point. Calculation: This QUESTION is based on ground to ground Projectile. We know that at the highest point of a projectile the instantaneous velocity of an object is equal to the x-axis component of the initial velocity. $\rm{ \therefore \: (v)_{highest \: point} = v_{x}}$ $\rm{ = > \: (v)_{highest \: point} = v \times \cos( \theta) }$ $\rm{ = > \: (v)_{highest \: point} = 20\times \cos( {20}^{ \circ} ) }$ $\rm{ = > \: (v)_{highest \: point} = 20\times 0.93 }$ $\rm{ = > \: (v)_{highest \: point} = 18.79 \: m {s}^{ - 1} }$ So, final ANSWER is: $\boxed{ \red{ \rm{ \: (v)_{highest \: point} = 18.79 \: m {s}^{ - 1} }}}$