<h3>One reason we should know what the directions of the forces acting on an object is so we can know if we have to add or subtract. same = add together, opposite = subtract from each other. Also if we don't pay attention to the direction the Net force will be wont be accurate. There will be factors that will upset the calculation.So we must know the direction of the two forces because we have to know if we are adding or subtracting and if the answer is accurate. </h3>
<em>I hope this helps!.</em>
kinetic energy because the bird is in motion
Answer:
959183.7 kg
Explanation:
from the question we have :
young modulus = 5 x 10^{9} N/m^{2}
strain = 2% = 2÷100 = 0.02
diameter = 0.03 m
radius = 0.015 m
acceleration due to gravity (g) = 9.8 m/s^{2}
we can get the mass from the formula below
young modulus = stress ÷ strain
where
stress = \frac[force}{area} = \frac {mass x g}{area}
area = 2πr = 2π x 0.015 = 0.094
therefore
young modulus = \frac{\frac {mass x g}{area}}{strain}
5 x 10^{9} = \frac{\frac {mass x 9.8}{0.094}}{0.02}
mass = \frac{5 x 10^{9} x 0.02 x 0.094}{9.8}
mass = 959183.7 kg
Explanation:
Using Kinematics,
We have v = u + at.
=> v = (5m/s) + (2.0m/s²)(4.0s)
=> v = 13m/s.
Hence the child's speed is now 13m/s.
