Answer:
In an ideal pulley system is assumed as a perfect system, and the efficiency of the pulley system is taken as 100% such that there are no losses of the energy input to the system through the system's component
However, in a real pulley system, there are several means through which energy is lost from the system through friction, which is converted into heat, sound, as well as other forms of energy
Given that the mechanical advantage = Force output/(Force input), and that the input force is known, the energy loss comes from the output force which is then reduced, and therefore, the Actual Mechanical Advantage (AMA) is less than the Ideal Mechanical Advantage of an "ideal" pulley system
The relationship between the actual and ideal mechanical advantage is given by the efficiency of the pulley system as follows;
Explanation:
Missing question: "What is the spring's constant?"
Solution:
The object of mass m=6.89 kg exerts a force on the spring equal to its weight:
When the object is attached to the spring, the displacement of the spring with respect to its equilibrium position is
And by using Hook's law, we can find the constant of the spring:
Answer: b
Explanation:
When heat is released by the system i.e. system loses heat. So, we take it as negative -Q
When the work is done on the system then it is considered as negative work on the system i.e. -W
In this case, the plunger is pulled out, and work is done on the system. So, we take work as negative work -W
Correct option is b
Answer:
4086 J
Explanation:
The potential energy is transformed to kinetic energy less the frictional energy. Potential energy= mgh where m represent mass, g is acceleration due to gravity and h is the height of cliff
Since we have force of air resistance, work done due to air resistance will be product of force and distance
Substituting 10 Kg for m, 9.81 for g and 60 m for F then the kinetic energy at the bottom will be
KE= 10*9.81*60- (30*60)=4086 J
Answer: The common difference between surface EMG and intramuscular EMG is that that former is non-invasive while the later is an invasive method
Explanation:
Electromyography (EMG) is used clinically for the examination of muscle excitations (muscle electrical activity) in both normal or abnormal conditions. There are two forms of EMG includes:
--> Surface EMT and
--> Intramuscular EMT
Surface EMT is a non invasive method of examination of muscle excitations for superficial and easily accessible muscles.
Intramuscular EMT is the invasive method of examination of muscle excitations usually for deep muscles.
The difference between the two forms of EMT includes:
- surface EMT is non- invasive while intramuscular EMT is invasive
- surface EMT is used to access superficial muscle while intramuscular EMT is used to access deep muscles.
- surface EMT requires less skill and time to carry out while intramuscular EMT requires special skills and takes more time while carrying out the procedure.
