Which one is it? Chemical, or ,Mechanical Flakes of brick fall off due to wind and rain.
2 answers:
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Answer:
v = (-4.44 i^ + 6.66 j^ ) m/s, a_average =( 0 i^ -2π j^) m/s²
Explanation:
The expression left corresponds to an oscillatory movement (MAS), the speed is defined by
v = dr / dt
the function of position
r = 2 cos πt i^ + 3 sin πt j^
let us note that it is a movement in two dimensions
let's perform the derivative
v = -2π sin πt i^ + 3π cos πt j^
we evaluate this expression for t = 0.25 s, remember that the angle is in radians
v = -2π sin (π 0.25) i^ + 3π cos (π 0.25) j^
v = (-4.44 i^ + 6.66 j^ ) m/s
To calculate the mean acceleration we use the expression
a = () / Δt
indicates that the time is the first 3 s
we look for the initial velocity t = 0 s
v₀ = 0 i ^ + 3π j ^
we look for the fine velocity, t = 3 s
v_f = - 2π sin (π 3) + 3π cos (π 3) j ^
v_f = 0 i ^ - 3π j ^
we calculate the average acceleration
Δt = (3 -0) = 3 s
a_average = (0-0) / 3 i ^ + (-3π - 3π) / 3
a_average = (0 i ^ -2π j ^ ) m/s²
GiveN:
- Initial velocity = 9.8 m/s²
- Accleration due to gravity = -9.8 m/s²
- Time taken = 1 s
To FinD:
- Final velocity of the ball?
Step-by-step Explanation:
Using the first Equation of motion,
⇒ v = u + gt
⇒ v = 9.8 + -9.8(1)
⇒ v = 0 m/s
The final velocity is hence <u>0</u><u> </u><u>m</u><u>/</u><u>s</u><u>.</u>
<h3>Note:</h3>- While solving questions of under gravity motions using equations of motion, remember the sign convection to avoid mistakes.
- You can consider positive above the ground and negative for towards it.