Answer:
Christian Doppler
Explanation:
The Scientist with the most significant contribution to the discovery of planets around other stars is Christian Doppler and his work that made this discovery possible is the Principle of DOPPLER EFFECT
<em>Christian Doppler was an Austrian scientist and physicist whose principle Doppler effect explained how observed frequency of light and sound waves are affected by a relative motion of both the source and detector </em>
"Constant velocity" is another way of saying "zero acceleration".
The top pair of pliers failed to loosen a stubborn bolt, but the bottom pair successfully removed it. Because the contact between the bolt and the pliers working surface is less.
<h3>What is mechanical advantage ?</h3>
Mechanical advantage is a measure of the ratio of output force to input force in a system, it is used to obtained efficiency of the given mechanical machine.
The efficiency to open the stubborn bolt depends upon the contact between the working surface of the pliers and the bolt.
The contact between the bolt and the top pair of pliers working surface is less. Its mechanical advantage is less.
Hence, the top pair of pliers failed to loosen a stubborn bolt, but the bottom pair successfully removed it.
To learn more about the mechanical advantage, refer to the link;
brainly.com/question/7638820
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Answer:
A
Explanation:
<em>The gold used in the making of jewelry is usually not pure but a heterogeneous mixture of metals. Pure gold is quite soft and even though it may look better in appearance compared to those made using heterogeneous mixtures, it usually bends easily. Hence, in order to make the jewelry more durable, gold is usually mixed with other metals to form a heterogeneous mixture. </em>
The correct option is A.
Answer:
Explanation:
Given
Initial reading on scale =40 N
So, we can conclude that weight of the sack is 40 N
After this a 10 N force is applied upward on the sack such that the net force becomes (40-10) N downward (because downward force is more)
This net downward force is the resultant of earth graviational pull and the applied upward force.
So, this downward force acts on the machine which inturn applies an upaward force of same magnitude called Normal reaction.
This situation can be diagramatically represented by figure given below
