Answer:
Explanation:
given,
weight of swimmer = 510 N
length of ledge, L = 1.75 m
vertical height of the cliff, h = 9 m
speed of the swimmer = ?
horizontal velocity of the swimmer should be that much it can cross the wedge.
distance = speed x time
d = v_x × t
1.75 = v_x × t ........(1)
now,time taken by the swimmer to cover 9 m
initial vertical velocity of the swimmer is zero.
using equation of motion for time calculation
t² = 1.938
t = 1.39 s
same time will be taken to cover horizontal distance.
now, from equation 1
1.75 = v_x × 1.39
horizontal speed of the swimmer is equal to 1.26 m/s
Answer:
the speed of the center of mass stays the same
Explanation:
In a system with no energy loss, momentum is conserved if the mass remains constant. The system described has no change in mass, and energy loss is considered negligible. Hence the product of the total mass and the velocity of its center will be a constant. The center of mass stays the same speed.
KE=1/2 mv²
= 1/2 × 70 × (6)²
= 1260
Answer: b. Throw it directly away from the space station.
Explanation:
According to <u>Newton's third law of motion</u>, <em>when two bodies interact between them, appear equal forces and opposite senses in each of them.</em>
To understand it better:
Each time a body or object exerts a force on a second body or object, it (the second body) will exert a force of equal magnitude but in the opposite direction on the first.
So, if the astronaut throws the wrench away from the space station (in the opposite direction of the space station), according to Newton's third law, she will be automatically moving towards the station and be safe.
