A quarterback throws a football at 40 km/hr to a receiver 50 yd away. How much time does it take the ball to reach the receiver? Would 40 km/hr be a acceleration or a velocity?

Question

anonymous · Answer

Hello there, 

When you are trying to identify what kind of variable a value is, it can be helpful to consider just the units.  Velocity is always measured by a distance/time (generally m/s).  Accelerations are written as a distance/time/time (generally m/s/s)  So in this case, given a distance/time, 40 km/hr is a velocity.  

To solve a problem involving fixed speeds and distances, you will want to use the equation: d=rt or d=vt, where d is the distance traveled, t is travel time, and r is the rate (rate and velocity are interchangeable here).  Since you are given the rate or velocity, and you are given the distance, you plug those in and solve for t.

This particular problem requires you to convert at least one of the values given to new units.  At minimum you need to convert the distance into km so that the units match up.