Need Help, Please Physics Homework, Final tomorrow Please

[cillaxe]

1)A 3kg heavy winter coat hangs in the middle of a clothesline causing it to sag by an angle of 5 degrees. Find the tension in the clothesline.

2). A car is traveling with a constant speed when the driver suddenly applies the brakes giving the car a deceleration of 4 m/s^2. If re car. Comes to a stop in a distance of 40 meters. What was re cars original speed?

 

[Defennder]

Hi, the same rules apply here. You need to show your work before others can help you. The first one is just resolving forces along the clothesline. The second one requires one of the three basic kinematics equations.

 

[thomate1]

1) To find the tension in the clothesline, we can use the equation T = mg tanθ, where T is the tension, m is the mass of the coat, g is the acceleration due to gravity (9.8 m/s^2), and θ is the angle of sag (5 degrees in this case). Plugging in the values, we get T = (3 kg)(9.8 m/s^2) tan(5 degrees) = 0.263 N. Therefore, the tension in the clothesline is 0.263 N.

2) We can use the equation v^2 = u^2 + 2as, where v is the final speed (0 m/s in this case), u is the initial speed (what we are trying to find), a is the deceleration (-4 m/s^2), and s is the distance (40 meters). Plugging in the values, we get 0^2 = u^2 + 2(-4 m/s^2)(40 m), which simplifies to u = 8 m/s. Therefore, the car's original speed was 8 m/s before the brakes were applied.