Answer:
54 km/h
Explanation:
given,
speed of the biker = 36 Km/h
time = 10 s
acceleration = 0.5 m/s²
speed at which it crosses the finish line = ?
v = 36 x 0.278 = 10 m/s
using equation of motion
v = u + a t
v = 10 + 0.5 x 10
v = 15 m/s
v = 15 x 3.6 = 54 km/hr
speed at which the biker crosses the finish line is equal to 54 km/h
Answer:
P = 10 kPa
Explanation:
Given that,
The mass of a small table, m = 4 kg
The area of each leg = 0.001 m²
We need to find the pressure exerted by the table on the floor. Pressure is equal to the force per unit area. So

So, the required pressure is 10 kPa.
The answer is C. Electrical;mechanical
Answer:
The reactance of the capacitor
Explanation:
In an AC circuit containing different elements (capacitors, resistors and inductors), we cannot simply calculate the equivalent resistance of the circuit, so another quantity is used, which is called reactance.
For a capacitor, the reactance is given by:

where:
f is the frequency of the AC current in the circuit
C is the capacitance of the capacitor
The reactance has a similar meaning to that of the resistance for a DC current. In fact, we notice that:
- When f=0 (which means we are in regime of DC current, because the current never changes direction), the reactance is infinite. This is correct: in a DC circuit, the capacitor does not let current pass through it, so it like it has infinite resistance (=infinite reactance)
- When f tends to infinite, the reactance becomes zero: in such situation, the current in the circuit changes direction so quickly that the capacitor has no enough time to "block" the current in the circuit, so it like it has almost zero resistance (zero reactance).