Answer:
Explanation:
Remark
This is a second class lever. It is much more efficient than the fishing pole problem. All distances are measured from the pivot in these kinds of questions.
Givens
d1 = 1.5
d2 = ?
m1 = 50 kg
m2 = 30 kg
The lighter child will have to sit further away from the pivot to make the two conditions equal.
Formula
d1*m1 = d2*m2
1.5*50 = d2 * 30
75 = 30 * d2
75/30 = d2
d2 = 2.5
Remark
Notice that the distance is longer for the lighter child. The fact that these are masses and not forces does not matter, but you should take note of it. There is a difference between masses and forces. See the fishing pole problem.
Answer to the multiple Choice question. No motion on this kind of problem means equal moments. The answer is D
Problem 2
1) The wheels are further apart making B more stable. The wider the distance the wheels are apart, the harder it would be to tip the concrete mixer over
2) The center of gravity is lower. The higher the force is the more chance you have of exerting an external force to tip the mixer over.
Answer:
Explanation:
Gravitational force between two objects having mass m₁ and m₂ at a distance R
F = G m₁ m₂ / R²
Force between baby and father F₁ = 6.67x10⁻¹¹ x 4.1 x 120 / .18²
= 1.01 x 10⁻⁶ N
b )
Force between baby and Jupiter
F₂ = 6.67x10⁻¹¹ x 1.9x 10²⁷ x 4.1 / ( 6.29 x 10¹¹ )²
= 1.31 x 10⁻⁶ N
c )
Ratio = 1.01 / 1.31
= .77
Answer: "B" Changing Position
Great Question!
Explanation: <u><em>When a ball bounces to the ground it hits the ground with some energy. The amount of energy with which it hits the ground is kinetic energy. When it comes in the contact with the ground kinetic energy gets converted into potential energy. This potential energy again gets converted into kinetic energy and balls moves again from the ground and bounces multiple times. So, the ball ends up changing position</em></u>
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Answer:
Explanation:
Given
Velocity of point is given by 
To get maximum or minimum velocity differentiate v w.r.t t
so 
should be equal to zero
i.e. 
