What type of accidents are among the most common cause of serious work related injuries and deaths
2 answers:
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Answer:
4.15 m/s
Explanation:
As the total energy must be conserved (neglecting air resistance) the change in gravitational potential energy, must be equal to the change in kinetic energy:
ΔE = ΔK + ΔU =0
If we take as a zero reference level for the gravitational potential energy, the height of the swing seat above the ground, (which is equal to 0.21 m), we can find the initial gravitational energy, considering the height of the point where the seat is released, regarding this point:
h₀ = 1.09 m -0.21 m = 0.88 m
⇒ U₀ = m*g*h₀ = 400 N*0.88 m = 352 J
As Uf = 0, ΔU = Uf -U₀ = -352 J
As the swing starts from rest, K₀=0, so we can say:
ΔK = Kf = (1)
As ΔK = -ΔU ⇒ ΔK = 352 J (2)
From (1) and (2) we can solve for vf, as follows:
So, when the swing passes through its lowest position, Betty moves at 4.15 m/s.
#1
Jill and Scott both moves for 30 minutes
now if Jill cover 5 km distance and Scott cover 10 km distance
now we know that the formula of speed is given as
now we will have
speed of Jill
speed of Scott
so correct answer here is
<em>Scott had the faster speed since he rode at 20 k/h while Jill only traveled 10 km/h.</em>
<em>#2</em>
distance travelled by each car is given as
now here it is given that
time taken by green car
time taken by yellow car
now we can find the speed of two cars
speed of green car
speed of yellow car
so correct answer will be
<em>The yellow car was faster. Yellow traveled at a speed of 50 mph while green was traveling at an average of 40 mph.</em>