# Tag Info

Accepted

### How do atoms and quantum mechanics create Hooke's Law for a spring

Like Ohm's law, Hookes law is not really a physics law, but an empirical conjecture that for most materials stress dependence on strain (i.e., the force dependence on displacement of a spring) has a ...
• 62k

### Definition of impulse

My question is: why would you write definition (1) when definition (2) is equivalent and much simpler? Equation (2) is really useful if you know a priori the momenta as a function of time. In the ...
• 28.5k

### Definition of impulse

My question is: why would you write definition (1) when definition (2) is equivalent and much simpler? I wouldn't. Although eq (1) defines the impulse of force where the force varies in time, eq (2) ...
• 76k
Accepted

### Trying to explain why $W = ΔKE$ and not $ΔE$

but for some reason, gravity did not remove any energy from the crate. That’s not true. Gravity did negative work of $-mgh$ on the crate. The work is negative because the force of gravity is in the ...
• 76k
1 vote

### Trying to explain why $W = ΔKE$ and not $ΔE$

Work is about energy changing from one form to another. For example, when you lift the crate, you convert chemical energy into gravitational potential energy. If you drop the crate, you convert ...
• 42.8k
1 vote

### Why is resolving vectors in some ways WRONG?

I also had this doubt in me when i was studying NLM . Whenever you have to resolve forces you always do them along and prependicular to the direction of motion For example- in the first problem the ...
1 vote

### Why is resolving vectors in some ways WRONG?

I am also solving this problem and I also made the same mistake. I've now finally understood what I got wrong and I think it will also benefit you: So what you did was split $u$ into its components ...
1 vote

### Why tension in a spring is equal to spring force

The tension force equals the spring force in the case where the string and spring are connected and massless. Consider a small sliver of the string/spring located at the intersection of the string and ...
1 vote

### Why tension in a spring is equal to spring force

Consider a point P at the junction between the spring and string .The point mass P has negligible mass and if the net force acting on it is non zero , the acceleration of point P will tend to infinity ...
1 vote
Accepted

### Definition of impulse

This is a soft question, so the best I can offer is a soft answer. You are correct that the two forms are equivalent. Either one could be taught as the definition. The force based definition ...
• 50.8k

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