If a sunspot appears only 70 s bright as the surrounding photosphere, and the photosphere has a temperature of approximately 578
1 answer:
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Answer:
Explanation:
The motion of a projectile consists of two independent motions:
- A uniform motion along the horizontal direction (constant velocity)
- A uniformly accelerated motion along the vertical direction (constant acceleration)
The time of flight of a projectile is given by
where
is the initial vertical velocity
is the acceleration due to gravity
Here the time of flight is
t = 8 s
So, the initial vertical velocity is:
At the same time, the horizontal distance covered by the projectile is given by
where
is the horizontal velocity, which is constant
t is the time of flight
Here we know that the range of the projectile is 0.3 km, so
d = 0.3 km = 300 m
So the horizontal velocity is
Therefore, we can find the angle of projection of the projectile by using:
Answer:
α = 1.114 × 10⁻³ (°C)⁻¹
Explanation:
Given that:
Length of rod (L) = 1.5 m,
Diameter (d) = 0.55 cm,
Area (A) =
Radius (r) = d / 2 = 0.275 cm,
Voltage across the rod (V) = 15.0 V.
At initial temperature (T₀) = 20°C, the current (I₀) = 18.8 A while at a temperature (T) = 92⁰C, the current (I) = 17.4 A
a) The resistance of the rod (R) is given as:
Therefore the resistivity and for the material of the rod at 20 °C (ρ) is:
b) The temperature coefficient of resistivity at 20°C for the material of the rod (α) can be gotten from the equation:
Rearranging to make α the subject of formula: