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Đáp án D
Lean your shoulders back and your waist forwards. Use your arms as a counter weight.
Answer:
v = 17.66 m/s
Explanation:
As we know that the lower end of the pole is fixed in the ground and it start rotating about that end
so here we can say that the gravitational potential energy of the pole will convert into rotational kinetic energy of the pole about its one end
so we have

so we have

now we have


now the speed of the other tip of the pole is given as


Answer:
force at the top will be 388 N which is nearly equal to 389
option (b) is correct
Explanation:
We have given velocity of the moving car v = 10 m/sec
Radius of the circular section r = 30 m
Mass of the passenger m = 60 kg
Acceleration due to gravity 
At the top normal force is given by 
So force at top will be 
So force at the top will be 388 N which is nearly equal to 389
So option (b) is correct
Answer:
The speed of the center of mass of the two carts is 0.103 m/s
Explanation:
It is given that,
Mass of the air track cart, m₁ = 350 g = 0.35 kg
Velocity of air track cart, v₁ = 1.25 m/s
Mass of cart, m₂ = 280 g = 0.28 kg
Velocity of cart, v₂ = -1.33 m/s (it is travelling in opposite direction)
We need to find the speed of the center of mass of the two carts. It is given by the following relation as :


Hence, this is the required solution.