True I hope this helps you out
Answer:
1 W = 1 J / sec Definition of watt is 1 joule / sec
So if a bulb uses 75 J / sec it must use
75 J/s * 60 sec / min = 4500 J/min energy used by bulb
If bulb is 15% efficient then the light delivered is
P = 4500 J / min * .15 = 675 J / min
Answer:
Explanation:
Area A of the coil = .1 x .1 = .01 m²
no of turns n = 5
magnetic field B = .5 t²
Flux Φ perpendicular to plane passing through it.= nBA sin30
rate of change of flux
dΦ/dt = nAdBsin30 / dt
= nA d/dt (.5t²x .5 )
= nA x 2 x .25 x t
At t = 4s
dΦ/dt = nA x 2
= 5x .01 x 2
= .1
current = induced emf / resistance
= .1 / 4
= .025 A
= 25 mA.
Answer:
t = 16.94 s
Explanation:
t is the time passes before police catch the speeder
speed of speeder Vo = V = 23.3 m/s
T = t
Police Info
Vo = 0 m/s
a = 2.75 m/s^2
t = t
Now,
displacement of the police car = displacement of the speeder.
x_{police} = Vo *t + 1/2 at^2
since Vo = 0
x police = 1/2 at^2
x police = 1/2 (2.75)(t)^2
Now the displacement of speeder is
x_{speeder} = Vt
x_{speeder} = 23.3 t
x_{speeder} = x_{police}
23.3 t = 1/2 * 2.75 t^2
23.3 t = 1.375 t^2
t = 23.3\1.375
t = 16.94
t = 16.94 s
