Given: Heat Qout means useful work = 2800 J
Heat Qin = 8900 J
Required; Efficiency = ?
Formula: Efficiency = Qout/Qin = x 100%
= 2800 J/8900 J = 0.3146 X 100 %
Efficiency = 31.46%
Answer:
60 kg m/s
Explanation:
Let
be the acceleration of the object.
As the acceleration of the object is constant, so

Given that applied force, F=6.00 N,
From Newton's second law, we have
,
[from equation (i)]


[given that time, t=10 s and F=6 N]

Here mv is the final momentum of the object and mu is the initial momentum of the object.
So, the change in the momentum of the object is mv-mu.
Hence, the change in the momentum of the object is 60 kg m/s.
Answer: 
Explanation:

where;
= final velocity = 0
= initial velocity = 60 km/h = 16.67 m/s
= acceleration
= distance
First all of, because acceleration is given in m/s and not km/h, you need to convert 60km/h to m/s. Our conversion factors here are 1km = 1000m and 1h = 3600s

Solve for a;

Begin by subtracting 

Divide by 2d

Now plug in your values:



If you're wondering why I calculated acceleration first is because in order to find force, we need 2 things: mass and acceleration.

m = mass = 900kg
a = acceleration = -2.78m/s

It's negative because the force has to be applied in the opposite direction that the car is moving.
Answer: Electric field vector is created by an electric force of a charged particle.
Explanation: The direction of the field vector can be determined by applying Coulomb’s Law which explains the electric force between charge particles. If q is positive the force is repulsive, to a test charge ( which is positive always ) and if q is negative the force is attractive to a test charge.