Sound travels at a speed of about 340m/s in the air. How long will it take an explosion to be heard from a distance of 20 miles
1 answer:
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If the object is moving at a constant speed, acceleration is 0. So:
The resultant force is 0. So the force pushing the object must be equal to the friction force acting, so
Friction = 90 N
The resultant force is 0. So the force pushing the object must be equal to the friction force acting, so
Friction = 90 N
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.