20km every 1 hr is what 20km/hr means.
so 3hrs is 20km*3=60km.
The correct option is C. i.e. <span>Using more coils of wire
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Explanation:
The strength of an electromagnet can be increased in the following ways:
1. By increasing the number of coils.
2. By increasing the current/voltage
3. Using an iron core, increases the strength of the electromagnet.
Answer:
A)s = 104.16 m
b)s= 104.16 m
Explanation:
Given that
u = 25 m/s
μ = 0.3
The friction force will act opposite to the direction of motion.
Fr= μ m g
Fr= - m a
a=acceleration
μ m g = - m a
a= - μ g
a= - 0.3 x 10 m/s² ( take g= 10 m/s²)
a= - 3 m/s²
The final speed of the mass is zero ,v= 0
We know that
v² = u² +2 a s
s=distance
0² = 25² - 2 x 3 x s
625 = 6 s
s = 104.16 m
By using energy conservation
Work done by all the forces =Change in the kinetic energy
Negative sign because force act opposite to the displacement.
- 3 x 2 x s = - 625
s= 104.16 m
Answer:
v = 3.08 km/s
Explanation:
Given that,
The angular velocity of the satellite =
A satellite is in orbit 36000km above the surface of the earth.
The radius of the earth is 6400 km
Let v is the velocity of the satellite. It can be calculated as :
So, the velocity of the satellite is 3.08 km/s.