- Initial velocity=u=72km/h
Convert to m/s

- Final velocity=v=0m/s
- Time=2s=t




Using second equation of kinematics





Now
Using newtons second law



- Force is in opposite direction so its negative

Answer:
m = 50 [kg]
Explanation:
The potential energy can be calculated by means of the following equation.

where:
Ep = potential energy = 735 [J]
m = mass [kg]
g = gravity acceleration = 9.81 [m/s²]
h = elevation = 1.5 [m]
Now replacing:
![735=m*9.81*1.5\\m = 50 [kg]](https://tex.z-dn.net/?f=735%3Dm%2A9.81%2A1.5%5C%5Cm%20%3D%2050%20%5Bkg%5D)
Answer:
<u>
</u>
Explanation:
Normal reaction from 40 kg slab on 10 kg block
M × g = 10 × 9.8 = 98 N
Static frictional force = 98 × 0.7 N
Static frictional force = 68.6 N is less than 100 N applied
10 kg block will slide on 40 kg slab and net force on it
= 100 N - kinetic friction

= 100 - 39.2
= 60.8 N




Frictional force on 40 kg slab by 10 kg block = 98 × 0.4
Frictional force on 40 kg slab by 10 kg block = 39.2 N


40 kg slab will move with = 

Answer:
D) Three times as many workers are needed
Explanation:
Let the number of workers needed for this project be x. Then the total number of man-month needed for this project originally (3 months) is x * 3 = 3x man month. Now since the government wants to reduce the time length from 3 months to 1 month then the new number of workers needed is
3x / 1 = 3x
So 3 times the original amount. D) is the correct answer