Step 1: Find the total time the object is in the air
The question says the object crosses a certain point after 2.3 s , then takes 5.7 s from that point to reach the ground. So, the total time in the air is:
T=2.3 s+5.7 s=8 sStep 2: Find the time taken to reach the maximum height
For a projectile (an object thrown at an angle), the time to go up to the highest point is half of the total time in the air:
tmax=2T=28 s=4 sStep 3: Find the starting upward speed using the motion formula
At the highest point, the speed going up becomes zero. The formula is:
vf=vi−gtmaxHere,
vf=0 (since upward speed is zero at the top),
g=10 m/s2, and
tmax=4 s :
0=vi−(10×4)vi=40 m/sStep 4: Calculate the maximum height reached
We use another formula to find the highest point:
Hmax=vitmax−21gtmax2Plug in the values:
Hmax=(40 m/s)(4 s)−21(10 m/s2)(4 s)2(40×4)=160 m(4 s)2=16 s221×10×16=80 mHmax=160 m−80 m=80 mFinal Answer:The maximum height reached by the body is
80 m.