Answer:
Speed = 20 m/s
Explanation:
The speed of a bus is 72 km/h
The SI unit of speed is m/s
We need to convert it into m/s
We know that,
1 km = 1000 m
1 h = 3600 s
It means,
![s=72\ \dfrac{km}{h}\\\\=\dfrac{72\times 1000\ m}{3600\ s}\\\\=20\ m/s](https://tex.z-dn.net/?f=s%3D72%5C%20%5Cdfrac%7Bkm%7D%7Bh%7D%5C%5C%5C%5C%3D%5Cdfrac%7B72%5Ctimes%201000%5C%20m%7D%7B3600%5C%20s%7D%5C%5C%5C%5C%3D20%5C%20m%2Fs)
So, the speed of the bus is 20 m/s.
Answer:
an example of when friction is a hindrance, is if someone with shorts is sliding down a slide. their skin rubbing on the slide will cause friction and will slow them down. another example is if you're dragging a large wooden box across the floor. the wood and the floor interacting cause friction and will make it more difficult to push the box.
Explanation:
hope this helps :D
Answer:
While lifting two object the machine needs the different momentum for different mass object.
Explanation:
- Momentum is the quantity of motion contained in an object. Usually it is measured by the product of mass and velocity.
- Momentum of first mass = 2 kg × 2 m/sec = 4 kg m/sec
- Momentum of second mass = 4 kg × 3 m/sec = 12 kg m/sec
- So the machine requires higher mass in motion for second object ( i.e. momentum) than the first one while lifting.