a 75-kg refrigerator is located on the 70th floor of a skyscraper (300 meters above ground). what is the potential energy of the
1 answer:
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Answer:
b. The side the boy is sitting on will tilt downward
Explanation:
Initially, the seesaw is balanced because the torque exerted by the boy is equal to the torque exerted by the girl:
where
Wb is the weight of the boy
db is the distance of the boy from the pivot
Wg is the weight of the girl
dg is the distance of the girl from the pivot
When the boy moves backward, the distance of the boy from the pivot ( increases, therefore the torques are no longer balanced: the torque exerted by the boy will be larger, and therefore the side of the boy will tilt downward.
Answer:
The block's mass should be
Explanation:
Given:
Cart with mass
From the conservation of energy before mass is added,
Where amplitude of spring mass system,
spring constant
Now new mass is added to the system,
Here, given in question frequency is reduced to half so we can write,
Where frequency of system before mass is added,
frequency of system after mass is added.
Therefore, the block's mass should be
Answer:
52 mm/s (approximately)
Explanation:
Given:
Initial speed of the projectile is,
Angle of projection is,
Time taken to land on the hill is,
In a projectile motion, there is acceleration only in the vertical direction which is equal to acceleration due to gravity acting vertically downward. There is no acceleration in the horizontal direction.
So, the velocity in the horizontal direction always remains the same.
The horizontal component of initial velocity is given as:
Now, the velocity in the vertical direction goes on decreasing and becomes 0 at the highest point of the trajectory. So, at the highest point, only horizontal component acts.
Therefore, the projectile's velocity at the highest point of its trajectory is equal to the horizontal component of initial velocity and thus is equal to 52 mm/s.