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English · with Momo
Tell me about your weekend — where did you go?
I very like hiking. Yesterday we walked in the mountains since three hours.

A native speaker might say

I'm really into hiking. Yesterday we were up in the mountains for three hours.

Corrections

  • very like → really like“Very” cannot modify a verb on its own — “really like” is what a native speaker reaches for.
  • since three hours → for three hours“For” measures how long something lasted; “since” marks when it started.

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Subject

Physics, picked up at the exact line where it stopped making sense.

Explain what you think you understand, and your companion finds the gap — then checks it with a question and a chart, right there in the conversation.

Physics · Grade 10

I get that momentum is conserved in a collision. But the textbook says energy is conserved too, and the answer key still says some energy is lost. Which is it?
Both, and the word doing the work is “kinetic”. Total energy is always conserved — but when two objects stick together on impact, part of the kinetic energy turns into heat and deformation. Momentum has no such escape route: it stays put.

Quick check

Two carts collide and stick together. What is conserved?

A.Kinetic energy onlyB.Momentum onlyC.Both momentum and kinetic energy

Not quite. They stick together, so the collision is perfectly inelastic. Momentum still balances exactly — but some kinetic energy has become heat, so it is not conserved.

Kinetic energy in this collision (J)

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