Answer: Change in velocity: -10 m/s, acceleration=-2.5m/s
Explanation:
The question in english is written below:
The end of a robotic arm moves to the right at 8m s. Four seconds later it moves to the left at 2m/s. What is its change in velocity and what is its change in acceleration?
We have the following data:
Initial Velocity of the robotic arm: (to the right)
Final Velocity of the robotic arm: (to the left)
Variation in time:
Firstly we have to calculate the change in velocity , which is given by the following equation:
This means the resultant velocity is to the left
Now, we can find the acceleration , given by:
This means the acceleration is also to the left, however its magnitude is always positive:
5). D
The bolt of lightning is a stream of electrons flowing from
a negative to a positive part of a cloud, or either up or down
between a charged cloud and the ground.
6). D
It would be sedimentary rocks
Answer:
Explained below.
Explanation:
In electric heaters, the wire used is nichrome wires and it can resist oxidation. Whereas, in electric bulbs, wires used are called tungsten and they undergo Oxidation begins at high temperatures between 500°C and 1200°C. Therefore, we would can't interchange because tungsten wires need a protective film/inert gas to withstand the high temperatures so that the wires don't get weak and break.
The car travels at a speed of 25m/s.
<u>Explanation:</u>
Given-
Mass, m = 1500kg
Coefficient of friction, μk = 0.47
Distance, x = 68m
Speed, s = ?
We know,
and
F = μ X m X g
Therefore,
μ * m * g = m * a
μ * g = a
Let, g = 9.8m/s²
So,
We know,
where, v is the final velocity
u is the initial velocity
a is the acceleration
s is the distance
If the car comes to rest, the final velocity, v becomes 0.
So,
The car travels at a speed of 25m/s.