The bullet from a rifle travels at a speed of 3*10^4 cm/s.Work out the length of time in seconds taken for the bullet to hit a target 54m away.
Let's go back to our basics. The formula for distance is given by:
Distance = speed x time
Rearranging, we have:
Time = Distance/speed
Let's work in cm
1m = 100cm
54m = 5400cm
Substituting this value (in cm) into the formula for time, we have:
= 5400 / speed
= 5400 / 30000
= 0.18 (secs)
The bullet will take 0.18 sec [that's about 1/5 of a second!] to reach its target.
A gentle note:
Be very careful with what units you are using. Speed can be in km/h, m/s, cm/s etc. Substituting the wrong values for the formula can have grave consequences.
The distance of the terget = 54meter.
Speed of the bullet = 3*10^4cm
Time taken to by the bullet = distance of the target /speed of the bullet. But here the speed of the bullet is given in centimeter per second. So we have to convert this into meter/second as the distance is in meter. For this we have to multiply the speed of the bullet by 0.01.
Therefore the speed of the bullet in m/s = 3*10^4*0.01 = 3*10^2 m/s.
Therefore the time taken by the bullet to reach the target = 54/3*10^2 s = 0.18 seconds.
Therefore the bullet takes 0.18 seconds to reacg the target.