Answer:
A. 490
Explanation:
soln
mass = m = 5kg
Height = h = 10m
Acceleration due to gravity = g = 9.8ms²
K.E = 1/2 × mass × (velocity)²
Recall from equations of motion
v² = u² + 2gh
Therefore,
K.E = 1/2 × mass × ( u² + 2gh)
K.E = 1/2 × 5 × ( 0² + 2×10×9.8)
K.E = 1/2 × 5 × 196
K.E = 1/2 × 980
K.E = 490 Joules
<span>The correct answer is B. - It would take a ray of light 10.5 light years to travel from Earth to Epsilon Eridani, or vice-versa. Using our current technology it would take far longer than 21.0 years for a space ship from Earth to travel that far - I would have to guess many hundreds of years.</span>
Answer: i think c
Explanation:QA: “What is ordinary glass made of ?”
Glass is mostly silica, or silicon dioxide, present as quartz in many types of sand. Pure silica forms a highly transparent glass, but has a very high melting or softening temperature, around 1700°C. Even at such high temperatures it is highly viscous and difficult to work. Its use is largely confined to applications requiring high transparency to ultra-violet and infra-red radiation, stability at elevated temperatures or low thermal expansion coefficient.
“Ordinary glass” windows and drinking vessels are typically made from soda-lime glass, containing silica with around 25% sodium, calcium and other oxides, which together reduce the softening temperature to roughly 500–600°C
