"<span>An atom is the smallest unit of matter and an element is a pure substance that is made of identical atoms" is correct. Although atoms can be broken down further now, it still take a whole atom to make an element. </span>
The kinetic energy of the phone right before it hits the ground is 9J.
<h3>
Kinetic energy of the phone</h3>
The kinetic energy of the phone right before it hits the ground is calculated as follows;
K.E = ¹/₂mv²
where;
- m is mass of the phone
- v is velocity of the phone
K.E = ¹/₂(0.08)(15)²
K.E = 9 J
Thus, the kinetic energy of the phone right before it hits the ground is 9J.
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The speed of the ball is 27.4 m/s
Explanation:
The speed of an object is given by:
where
d is the distance covered
t is the time taken
In this problem, we have:
d = 300 yards is the distance covered by the golf ball
t = 10 s is the time taken
Keeping in mind that
1 yard = 0.914 m
We can convert the distance from yards to meters:
And substituting into the equation, we find the speed of the ball:
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Answer:
85.8 m/s
Explanation:
We know that the length of the circular path, L the plane travels is
L = rθ where r = radius of path and θ = angle covered
Now,its speed , v = dL/dt = drθ/dt = rdθ/dt + θdr/dt
where dθ/dt = ω = angular speed = v'/r where v' = maximum speed of plane and r = radius of circular path
Now, from θ = θ₀ + ωt where θ₀ = 0 rad, ω = angular speed and t = time,
θ = θ₀ + ωt = 0 + ωt = ωt
So, v = rdθ/dt + θdr/dt
v = rω + ωtdr/dt
v = (r + tdr/dt)ω
v = (r + tdr/dt)v'/r
v = v' + tv'/r(dr/dt)
v = v'[1 + t(dr/dt)/r]
Given that v' = 110 m/s, t = 33.0s, r = 120 m and dr/dt = rate at which line is shortened = -0.80 m/s (negative since it is decreasing)
So, v = 110 m/s[1 + 33.0 s(-0.80 m/s)/120 m]
v = 110 m/s[1 + 11.0 s(-0.80 m/s)/40 m]
v = 110 m/s[1 + 11.0 s(-0.02/s)]
v = 110 m/s[1 - 0.22]
v = 110 m/s(0.78)
v = 85.8 m/s
