Danny is riding his bike at 12m/s he tries to pop a wheelie but he fails hits a curb flies through the air and comes to a complete stop in 30 seconds what is Danny's deceleration

Several mountains together form a mountain . a few of these combined form a mountain system. several systems combined form a mountain , which can stretch thousands of miles in length.

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The first law of thermodynamics states that heat added to a system is neither created nor destroyed but is as it changes into other forms of energy.