Answer:
a) 19440 km/h²
b) 10 sec
Explanation:
v₀ = initial velocity of the car = 45 km/h
v = final velocity achieved by the car = 99 km/h
d = distance traveled by the car while accelerating = 0.2 km
a = acceleration of the car
Using the kinematics equation
v² = v₀² + 2 a d
99² = 45² + 2 a (0.2)
a = 19440 km/h²
b)
t = time required to reach the final velocity
Using the kinematics equation
v = v₀ + a t
99 = 45 + (19440) t
t = 0.00278 h
t = 0.00278 x 3600 sec
t = 10 sec
Kinetic energy is the energy for a catapult.
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:
Magnetic substances: steel tank, iron ball, nickel hinge
Non magnetic substances: wooden table, glass marbles, silver medal.
Explanation:
The substances which experience a force of attraction when placed in a magnetic field are called magnetic substances. For example, iron, cobalt and nickel.
The substances which do not experiences a force of attraction when placed in a magnetic field are called non magnetic substances. For example, wood, rubber, glass, etc.
This is TRUE everything has a action the force from your feet pushes and the floor pushes back