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SIZIF [17.4K]
4 years ago
13

While a roofer is working on a roof that slants at 39.0 degrees above the horizontal, he accidentally nudges his 88.0 N toolbox,

causing it to start sliding downward, starting from rest.
If it starts 4.90 m from the lower edge of the roof, how fast will the toolbox be moving just as it reaches the edge of the roof if the kinetic friction force on it is 18.0 N ?
Physics
1 answer:
Ostrovityanka [42]4 years ago
5 0

Answer:

V= 6.974 m/s

Explanation:

Component( box) weight acting parallel and down roof 88(sin39.0°)=55.4 N

Force of kinetic friction acting parallel and up roof = 18.0 N

Fnet force acting on tool box acting parallel and down roof

Fnet= 55.4 - 18.0

Fnet=37.4 N

acceleration of tool box down roof

a = 37.4(9.81)/88.0

a= 4.169 m/s²

d = 4.90 m

t = √2d/a

t= √2(4.90)/4.169

t= 1.662 s

V = at

V= 4.169(1.662)

V= 6.974 m/s

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Two spectators at a soccer game in Montjuic Stadium see, and a moment later hear, the ball being kicked on the playing field. Th
Akimi4 [234]

Answer:

a) The distance of spectator A to the player is 79.2 m

b) The distance of spectator B to the player is 43.9 m

c) The distance between the two spectators is 90.6 m

Explanation:

a) Knowing the time it takes the sound to reach both spectators, we can calculate their position relative to the player, using this equation:

x = v * t

where:

x = position of the spectators

v = speed of sound

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Then, the position for spectator A relative to the player is:

x = 343 m/s * 0.231 s = 79.2 m

b)For spectator B:

x = 343 m/s * 0.128 s

x = 43.9 m

The distance of spectator A and B to the player is 79.2 m and 43.9 m respectively.

c) To calculate the distance between the spectators, please see the attached figure. Notice that the distance between the spectators is the hypotenuse of the triangle formed by the sightline of both. We already know the longitude of the two sides. Then, using Pythagoras theorem:

(Distance AB)² = A² + B²

(Distance AB)² = (79.2 m)² + (43.9 m)²

Distance AB = 90. 6 m

6 0
3 years ago
Balanced forces can change an<br> object's direction.<br> A. True<br> B. False
makvit [3.9K]

Answer:

False

Explanation:

Balanced forces result in a net force of 0N. This means no direction or acceleration change will be applied to the object. A torque may be applied, but with no other external forces, the object will not move.

8 0
3 years ago
A group of students are playing tug-of-war. The students on both
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Answer:

newton's first law

Explanation:

this is because newton's first law of motion states that every object will continue in its state of rest or uniform motion in a straight line unless a resultant force acts on it.

hope this helps, if you want more elaboration, tell me

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3 years ago
Read 2 more answers
A ball of mass 0.50 kg is fired with velocity 160 m/s into the barrel of a spring gun of mass 1.8 kg initially at rest on a fric
shepuryov [24]

Answer:

All fraction of kinectic energy is lost to barrel of a spring gun of mass 1.8 kg

Explanation:

A ball of mass 0.50 kg is fired with velocity 160 m/s ...

The kinetic energy is given by 1/2mv²

Kinectic energy of the ball = 1/2 *0.5*160²

Kinectic energy = 1/4 *25600

Kinectic energy = 6400 joules.

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