<h3><u>Answer;</u></h3>
= 75 %
<h3><u>Explanation</u>;</h3>
To measure efficiency of a machine, compare the work output to work input.
Efficiency = Work output/ work output × 100 %
= 300/400 × 100
= 75 %
The x component of the force is 8.4N * cos(31°) = 7.2N (2 s.f.)
Answer:
The kinetic energy of the system after the collision is 9 J.
Explanation:
It is given that,
Mass of object 1, m₁ = 3 kg
Speed of object 1, v₁ = 2 m/s
Mass of object 2, m₂ = 6 kg
Speed of object 2, v₂ = -1 m/s (it is moving in left)
Since, the collision is elastic. The kinetic energy of the system before the collision is equal to the kinetic energy of the system after the collision. Let it is E. So,

E = 9 J
So, the kinetic energy of the system after the collision is 9 J. Hence, this is the required solution.
Answer:
C
Explanation:
It says is it a good idea the person so 1 person can say no and the other one can say yes so it is asks for a opinion