Significant digits show the precision of measurements and calculations
Answer:
42.96 km/s
Explanation:
From the conservation of Energy

Mass gets cancelled

= Escape velocity of Earth = 11.2 km/s
= Velocity of projectile = 44.4 km/s

The velocity of the spacecraft when it is more than halfway to the star is 42.96 km/s
Answer: 500 joules
Explanation:
Given that
Mass of ball = 10kg
kinetic energy = ?
velocity of the ball = 10m/s
Kinetic energy is the energy possessed by a moving object. It is measured in joules, and depends on the mass (m) of the object and the velocity (v) by which it moves
i.e K.E = 1/2mv²
K.E = 1/2 x 10kg x (10m/s)²
K.E = 0.5 x 10kg x (10m/s)²
K.E = 5 x 100
K.E = 500 joules
Thus, the kinetic energy of the ball is 500 joules
Answer:
128.21 m
Explanation:
The following data were obtained from the question:
Initial temperature (θ₁) = 4 °C
Final temperature (θ₂) = 43 °C
Change in length (ΔL) = 8.5 cm
Coefficient of linear expansion (α) = 17×10¯⁶ K¯¹)
Original length (L₁) =.?
The original length can be obtained as follow:
α = ΔL / L₁(θ₂ – θ₁)
17×10¯⁶ = 8.5 / L₁(43 – 4)
17×10¯⁶ = 8.5 / L₁(39)
17×10¯⁶ = 8.5 / 39L₁
Cross multiply
17×10¯⁶ × 39L₁ = 8.5
6.63×10¯⁴ L₁ = 8.5
Divide both side by 6.63×10¯⁴
L₁ = 8.5 / 6.63×10¯⁴
L₁ = 12820.51 cm
Finally, we shall convert 12820.51 cm to metre (m). This can be obtained as follow:
100 cm = 1 m
Therefore,
12820.51 cm = 12820.51 cm × 1 m / 100 cm
12820.51 cm = 128.21 m
Thus, the original length of the wire is 128.21 m
Here light ray strikes to interface at an angle of 45 degree and then refracts into other medium such that it will bend towards boundary.
So here the angle of incidence will be less than the angle of refraction as light moves towards the boundary after refraction which mean it will bend away from the normal
here it can be said that medium 2 will be rarer then medium 1
So here the possible options are
1. Water
Air
2. Diamond
Air
So in above two options medium 1 is denser and medium 2 is rarer