Choice ' C ' is a correct statement.
The other choices aren't.
Answer:
The tensile stress on the wire is 550 MPa.
Explanation:
Given;
Radius of copper wire, R = 3.5 mm
extension of the copper wire, e = 5.0×10⁻³ L
L is the original length of the copper wire,
Young's modulus for copper, Y = 11×10¹⁰Pa.
Young's modulus, Y is given as the ratio of tensile stress to tensile strain, measured in the same unit as Young's modulus.

Therefore, the tensile stress on the wire is 550 MPa.
Answer:
3.08m/s²
Explanation:
Given parameters:
Radius = 20m
Tangential velocity = 7.85m/s
Unknown:
Centripetal acceleration = ?
Solution:
Centripetal acceleration is the acceleration of a body along a circular path.
it is mathematically given as;
a =
v is the tangential velocity
r is the radius
a =
= 3.08m/s²
Scientists conduct multiple trial experiments because one test might not be as reliable as multiple trials. Another reason they conduct multiple trials is because the scientific method says to conduct multiple experimental tests.
The action or process of magnifying something or being magnified, especially visually. Hope this helped