Answer:
The force must he apply to the sled is of F= 764.4 N.
Explanation:
m= 60 kg
g= 9.8 m/s²
μ=0.3
W= m*g
W= 588 N
Fr= μ*W
Fr= 176.4 N
F= W + Fr
F= 764.4 N
Force=mass•acceleration
F=ma
15 N= 5kg•a
/5 =. /5
3= acceleration?
This is hard sorry but I need to anwser
Answer:
Worldwide Radio Communication
Explanation:
The ionosphere is important because it is through the ionosphere that world wide radio communication is possible.
The speed of sound at T=25°C is Vs=346 m/s. So the sound has to reach the cliff and return back to you so the path it needs to travel is s=2*440 m = 880 m.
Since the speed of sound is constant s=Vs*t, and t= s/Vs=880/346=2.54335 s. You will hear the echo after t=2.54335 s after you shouted.
