In which of the following cases is the torque about the shoulder due to the weight of the arm the greatest? Case 1: A person hol
1 answer:
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Answer:
Explanation:
The torque exerted is given by
where
is the force applied
d = 3.10 cm = 0.031 m is the length of the lever arm
Substituting,
The equivalent of Newton's second law for rotational motion is:
where
is the net torque
I is the moment of inertia
is the angular acceleration
Solving the equation for I, we find
The initial velocity of the sled will be 7.34 m/sec. V is the initial velocity of the sled.
<h3>What is the law of conservation of momentum?</h3>According to the law of conservation of momentum, the momentum of the body before the collision is always equal to the momentum of the body after the collision.
The given data in the problem is;
(m₁) mass of child = 38 kg
(u₁) is the initial velocity child = 2.2 m/s
(m₂) is the mass of sled = 68 kg
(u₂) is the initial velocity of sled = ?
(v) is the velocity after collision = 5.5 m/s
According to the law of conservation of momentum;
Momentum before collision =Momentum after collision
Hence,the initial velocity of the sled will be 7.34 m/sec.
To learn more about the law of conservation of momentum refer;
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1) 4 forces
2) 165 N
3) 225 N
Explanation:
1)
There are in total 4 forces acting on the bicylist:
- The gravitational force on the byciclist, acting vertically downward, of magnitude , where m is the mass of the bicyclist and g is the acceleration due to gravity
- The normal force exerted by the floor on the bicyclist and the bike, N, vertically upward, and of same magnitude as the gravitational force
- The force of push F, acting horizontally forward, given by the push exerted by the bicylist on the pedals
- The air drag, R, of magnitude R = 60.0 N, acting horizontally backward, in the direction opposite to the motion of the bicyclist
2)
The magnitude of the net force on the bicyclist can be calculated by considering separately the two directions.
- Along the vertical direction, we have the gravitational force (downward) and the normal force (upward); these two forces are equal in magnitude, since the acceleration of the bicyclist along this direction is zero, therefore the net force in this direction is zero.
- Along the horizontal direction, the two forces (forward force of push and air drag) are balanced, since the acceleration is non-zero, so we can use Newton's second law of motion to find the net force on the bicylist:
where
is the net force
m = 75.0 kg is the mass of the bicyclist
is its acceleration
Solving, we find the net force:
3)
In this part, we basically want to find the forward force of push, F.
We can rewrite the net force acting on the bicyclist as
where:
F is the forward force of push
R is the air drag
We know that:
is the net force on the bicyclist
R = 60.0 N is the magnitude of the air drag
Therefore, by re-arranging the equation, we can find the force generated by the bicylicst by pedaling: