Answer:
Option D. 4.4 m/s²
Explanation:
The following data were obtained from the question:
Velocity (v) = 21 m/s
Radius (r) = 100 m
Centripetal acceleration (a) =.?
The centripetal acceleration of the car can be obtained as follow:
Centripetal acceleration (a) = Velocity square (v²) / radius (r)
a = v²/r
a = 21²/100
a = 441/100
a = 4.41 ≈ 4.4 m/s²
Therefore, the centripetal acceleration of the car is 4.4 m/s².
Answer:
option c
Explanation:
Kinetic energy is due to the speed of a body.

When speed is doubled, the kinetic energy is quadruple.
From third equation of motion, braking distance is also proportional to square of speed. Thus, when speed is doubled, the braking distance is quadruple.
Thus, option c is correct.
Answer:
3.6 arcsec
Explanation:
angular diameter = diameter / distance
diameter is constant
so angular diameter ∝ 1 / distance
angular diameter = k / distance
For first case ,
18 = k / .5
for second case let angular diameter be D .
D = k / 2.5
dividing ,
D / 18 = .5 / 2.5 = 1 / 5
D = 18 / 5 = 3.6 arcsec
3.6 arcsec is the answer .
Answer:
No, the magnitude of the magnetic field won't change.
Explanation:
The magnetic field produced by a wire with a constant current is circular and its flow is given by the right-hand rule. Since this field is circular with center on the wire the magnitude of the magnetic field around the wire will be given by B = [(\mi_0)*I]/(2\pi*r) where (\mi_0) is a constant, I is the current that goes through the conductor and r is the distance from the wire. If the field sensor will move around the wire with a fixed radius the distance from the wire won't change so the magnitude of the field won't change.