Answer:
a) 20 m/s
b) 37.5 m)s
Explanation:
Average speed = total distance ÷ total time
=> (a) average speed of a car that travels 400m in 20s
= 400/20 = 20 m/s
& (b) average speed of an athlete who runs 1500m in 4 minutes (or 4×60=240 seconds)
= 1500/240 = 37.5 m/s
All you do is 0.5 times the mass times the kenetic energy hope this helps
This question s is really asking us to first find the length
of runway needed to achieve takeoff speed. Once we find this minimum length,
we’ll multiple it by three and compare it to a 2.5 mile runway. The simplest
way to solve for this minimum length is to use the answers to the last
questions. We will plug acceleration we found and the minimum time required
into
Δ
And we find the minimum runway length is 1.39 km or 0.863
miles (using the conversions in the inside cover of the text). The safe runway
length is then 2.59 miles. So, the 2.5 mile long runway in the question is too
short, by a smidgen, to launch this jetliner safely