Answer:
We know that force applied per unit area is called pressure.
Pressure = Force/ Area
When force is constant than pressure is inversely proportional to area.
1- Calculating the area of three face:
A1 = 20m x 10 m =200 Square meter
A2 = 10 mx 5 m = 50 Square meter
A3 = 20m x 5 m = 100 Square meter
Therefore A1 is maximum and A2 is minimum.
2- Calculate pressure:
P = F/ A1 = 30 / 200 = 0.15 Nm⁻² ( minimum pressure)
P = F / A2 = 30 / 50 = 0.6 Nm⁻² ( maximum pressure)
Hence greater the area less will be the pressure and vice versa.
Answer:
The correct option is (B).
Explanation:
The Kepler's third law of motion gives the relationship between the orbital time period and the distance from the semi major axis such that,
It is mentioned that, an asteroid with an orbital period of 8 years. So,
So, an asteroid with an orbital period of 8 years lies at an average distance from the Sun equal to 4 astronomical units.
Answer:
Explanation:
Given that,
Initial speed, u = 5 m/s
Final speed, v = 10 m/s
Time, t = 2 s
The radius of the tire of the bike, r = 35 cm
We need to find the angular acceleration of the pebble during those two seconds. It can be calculated as follows.
So, the required angular acceleration of the pebble is equal to 
.
Answer a) is incorrect as sound does not travel in a vacuum.
Answer:
To calculate anything - speed, acceleration, all that - we need <em>data</em>. The more data we have, and the more accurate that data is, the more accurate our calculations will be. To collect that data, we need to <em>measure </em>it somehow. To measure anything, we need tools and a method. Speed is a measure of distance over time, so we'll need tools for measuring <em>time </em>and <em>distance</em>, and a method for measuring each.
Conveniently, the lamp posts in this problem are equally spaced, and we can treat that spacing as our measuring stick. To measure speed, we'll need to bring time in somehow too, and that's where the stopwatch comes in. A good method might go like this:
- Press start on the stopwatch right as you pass a lamp post
- Each time you pass another lamp post, press the lap button on the stopwatch
- Press stop after however many lamp posts you'd like, making sure to hit stop right as you pass the last lamp post
- Record your data
- Calculate the time intervals for passing each lamp post using the lap data
- Calculate the average of all those invervals and divide by 40 m - this will give you an approximate average speed
Of course, you'll never find an *exact* amount, but the more data points you have, the better your approximation will become.
