John is going to use a rope to pull his sister Laura across the ground in a sled through the snow. He is pulling horizontally wi
1 answer:
Answer:
The mass of Laura and the sled combined is 887.5 kg
Explanation:
The total force due to weight of Laura and friction on the sled can be calculated as follows;
= (400 + 310) N
= 710 N
From Newton's second law of motion, "the rate of change of momentum is directly proportional to the applied force.
where;
is mass of Laura and
is mass of sled
Mass of Laura and the sled combined is calculated as follows;
given
V = Δv = 4-0 = 4m/s
t = 5 s
Therefore, the mass of Laura and the sled combined is 887.5 kg
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Answer:
It was proposed by Isaac Newton
Explanation:
The law of universal attraction of expression
F = G m1m2 / r ^ 2
where G is a constant, m₁ and m₂ are the masses of the bodies and r the distance between them.
It was proposed by Isaac Newton
With this law Newton explained that the force that pulls the moon towards the earth is the same as that which attracts an apple towards the earth
b) the net force on the car is zero.
Explanation:
Let's analyze each option one by one:
a) the force from the engine is greater than all the forces of friction. --> FALSE. In fact, the car is moving at constant velocity: this means that its acceleration is zero,
a = 0
and so Newton's second law becomes
where is the net force on the car and m is its mass. This means that the net force on the car is zero: so, the force from the engine cannot be greater than all the forces of friction, otherwise the net force cannot be zero.
b) the net force on the car is zero. --> TRUE, for what we said at point A)
c) the inertia is changing. --> FALSE. The inertia of an object just depend on the mass and the velocity of the object: as neither the mass nor the velocity are changing in this problem, then the inertia of the car is not changing.
d) the forces of friction are proportional to the acceleration of the car. --> FALSE. Generally, the force of friction acting on an object moving on a flat surface is
where is the coefficient of friction, m is the mass, and g the acceleration of gravity. Therefore, the force of friction does not depend on the acceleration of the car.
e) All of the above. --> FALSE
Learn more about net force and Newton's second law:
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