BlueLemonWater
08.07.2020 •
Physics
The position of an object moving along the x
axis is given by x(t) = 2t^2+t^3 +1, where x is
in meters and t in seconds. The acceleration of
the object at t = 2 seconds is:
4m/s?
Solved
Show answers
More tips
- S Science and Technology Colliders: How They Work and Why They Matter...
- S Science and Technology Exploring Our Galaxy: How Many Planets are in the Milky Way?...
- W Work and Career Everything You Need to Know About MBA Programs...
- B Business and Finance What is the Difference Between Visa and Visa Gold?...
- C Computers and Internet The Twitter Phenomenon: What it is and How to Use it...
- S Sport When and Where Will the 2014 World Cup be Held?...
- S Sport When is the Champions League final?...
- C Construction and repair How to Choose the Best Underfloor Heating?...
- A Animals and plants How ants survive winter: exploring the secrets of their winter life...
- A Auto and Moto How to Choose a Car Wash? Tips and Recommendations...
Answers on questions: Physics
- H History What problems does relying on an individuals memory bring to determine what happened in the past?...
- M Mathematics Which expression can be used to find the surface area of the following square pyramid? Choose 1 Choose 1 (Choice A) A 4+64+64, plus, 6 (Choice B) B 4+3+3+34+3+3+34,...
- A Advanced Placement (AP) Join my zoom if your lonely on halloween and want to talk. Id:5581900550 Password:45pin join if you want to talk or just bored on halloween cause i am...
- M Mathematics What is the answer to this question...
Ответ:
16 meters per second
Explanation:
The derivative of the position is the velocity.
The derivative of the velocity is the acceleration.
x(t) = 2t² + t³ + 1
x'(t) = v(t) = 4t + 3t²
x''(t) = v'(t) = a(t) = 4 + 6t
a(2) = 4 + 6(2)
= 4 + 12
= 16
Ответ:
Q1. i. In what two ways combustion can be useful to us? Explain by giving examples.
Ans1 i.Combustion is the burning of fuels in oxygen to release energy. It is useful to us in the following ways:
Combustion helps us to cook food.
Combustion helps us to power vehicles by burning fossil fuels to produce energy.
Combustion helps in keeping our home warm by burning coal and wood.
ii. Explain why decomposition of sugar on heating is an irreversible change.
Ans1. ii. Decomposition of sugar is an irreversible change because new substances are formed and a chemical reaction has taken place. It is therefore not possible to change the sugar back to its original form.
Q2. In order to answer this question you need to look around your immediate surroundings to find examples of rusting of iron or any other metal.
What makes iron rust?
Ans 2 i. Oxygen and water vapour in the air react with iron to form iron oxide. Iron oxide’s common name is rust. This causes the iron to rust.
Why is the rusting of iron a problem? Give any 3 examples from daily life where rusting has been a disadvantage.
Ans 2 ii. Rusting of iron is a problem because it happens on the surface of iron objects and makes them coarse and flaky. It also makes the iron objects fragile. The rust can also eat through the material and causes it to weaken.
Rusting of car bodies causes the body of the car to weaken and become more fragile and prone to breaking.
Oxygen and water vapour can react with iron bodies of water tanks and pipes and cause them to rust. This causes the metal to become weak.
Rusting can occur on iron towers and thus causes the quality of the metal to diminish.
Suggest any two ways that can help prevent rusting of iron.
The two ways that can help prevent rusting of iron are:
Keeping iron clean and dry can keep it from rusting because oxygen in water causes the iron to rust.
Coating the surface of a metal object with paint or varnish can also cause it to become immune to rusting.
Q3. i. Give two differences between a physical change and a chemical change.
Ans 3. i. The three differences between physical change and chemical change are:
During a physical change no new substance is formed whereas during a chemical change a new substance is formed.
During a physical change no energy is absorbed or given out whereas during chemical change energy is given out or absorbed.
During a physical change there is no change in the type of molecules. However, in chemical change there is a change in the type of molecules.
ii. Explain whether condensation of water vapour is a physical or a chemical change.
Ans 3 ii. Condensation of water is a physical change as no new substance is formed during condensation. Only the state of water is changed. Also, as no energy is given out or absorbed,condensation of water is an example of a physical change.
iii. Write word equations for the following reactions:
Breaking down/ electrolysis of water
Ans a. Electric current
Water Hydrogen + Oxygen
synthesis of water
Heat
Hydrogen + Oxygen Water
decomposition of sugar
Heat
Sugar Carbon + Water
photosynthesis in plants
Light
Carbon dioxide + water Glucose + Oxygen + Energy
Explanation: