C, due to stuff and whatnot
Which body is in equilibrium?
(1) a satellite orbiting Earth in a circular orbit
. No. The forces on it are unbalanced. There's only one force acting on it ... the force of gravity, pulling it toward the center of the Earth. That's a centripetal force, and the satellite is experiencing centripetal acceleration.
(2) a ball falling freely toward the surface of Earth. No. The forces on it are unbalanced. There's only one force acting on it ... the force of gravity, pulling it toward the center of the Earth. The ball is accelerating toward the ground.
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(3) a car moving with a constant speed along a straight, level road. YES.</em> We don't even need to analyze the forces, just look at the car. It's moving in a straight line, and its speed is not changing. The car's acceleration is zero ! That right there tells us that the NET force ... the sum of all forces acting on the car ... is zero. THAT's called 'equilibrium'.
(4) a projectile at the highest point in its trajectory. No. The forces on it are unbalanced. There's only one force acting on it ... the force of gravity, pulling it toward the center of the Earth. The projectile is accelerating toward the ground.
The acceleration of the car and the time required to reach this speed will be 8 m/s² and 10 sec.
<h3>What is acceleration?</h3>
The rate of velocity change concerning time is known as acceleration.
Given data;
Initial velocity, u=0 m/s
Final velocity, v= 80 m/sec
Distance travelled,s =900m
From Newton's third equation of motion;
v²=u²+2as
a =(v²-u²)/2s
Substitute the given values;
a = (80²-0)/2 ×900
a = 6400/1800
a=8 m/s²
The time required to reach this speed is found in Newton's first equation of motion as;
v = u+at
Substitute the given values;
80 = 0 + 8t
t=80/8
t = 10 sec
Hence, the acceleration of the car and the time required to reach this speed will be 8 m/s² and 10 sec.
To learn more about acceleration, refer to the link brainly.com/question/2437624
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