As a delivery truck travels along a level stretch of road with constant speed, most of the power developed by the engine is used
1 answer:
Answer:
128 N
Explanation:
Power can be defined as
<em>F</em> is the force and <em>v</em> is the velocity.
According to the question, <em>P</em> = 5.15 hp = 5.15 × 746 W.
<em>v</em> = 30 m/s
Since most of the power is used to compensate for the energy transformations due to friction forces, the total frictional is 128 N
You might be interested in
The force of friction is 300 N
Explanation:
We can solve the problem by applying Newton's second law of motion: in fact, the net force acting on an object is equal to the product between the mass of the object and its acceleration. So we can write
where
is the net force acting on the object
m is its mass
a is its acceleration
For the cart in this problem, we have two forces acting on it:
- The force of push, F = 500 N, forward
- The force of friction, , backward
So Newton's second law can be rewritten as
where
m = 50 kg
is the acceleration of the cart
And solving for , we find the force of friction:
Learn more about force of friction:
#LearnwithBrainly
Answer:
a) The work done by the applied force is 1500 joules.
b) The kinetic energy of the block after 10 seconds is 1200 joules.
c) The magnitude of the force of friction is 3 newtons and its direction is against motion.
d) 300 joules of energy are lost during motion.
Explanation:
a) Since the object has a constant mass, on which a constant horizontal force is exerted. The work done by the force (), measured in joules, is defined by the following expression:
(1)
Where:
- Force, measured in newtons.
- Distance, measured in meters.
If we know that and
, then the work done by the force exerted on the object is:
The work done by the applied force is 1500 joules.
b) At first we need to calculate the net acceleration of the object (), measured in meters per square second. By assuming a constant acceleration, we use the following kinematic formula:
(2)
Where is the initial velocity of the object, measured in meters per second.
We clear the acceleration within the equation above:
If we know that ,
and
, then the net acceleration experimented by the object is:
By the 2nd Newton's Law, we construct the following equation of equilibrium under the consideration of a friction force acting against the motion of the object:
(3)
Where:
- External force exerted on the object, measured in newtons.
- Kinetic friction force, measured in newtons.
If we know that ,
and
, the kinetic friction force is:
The work done by friction (), measured in joules, is:
(4)
And the net work experimented by the object is:
By the Work-Energy Theorem we understand that change in translational kinetic energy (), measured in joules, is equal to the change in net work. That is:
(5)
If we know that , then the change in translational kinetic energy is:
The kinetic energy of the block after 10 seconds is 1200 joules.
c) The magnitude of the force of friction is 3 newtons and its direction is against motion.
d) The energy lost by the object is equal to the work done by the force of friction. Therefore, 300 joules of energy are lost during motion.