Answer:
the velocity is zero, the acceleration is directed downward, and the force of gravity acting on the ball is directed downward
Explanation:
Is this exercise in kinematics
v = v₀ - g t
where g is the acceleration of the ball, which is created by the attraction of the ball to the Earth.
At the highest point
velocity must be zero.
The acceleration depends on the Earth therefore it is constant at this point and with a downward direction.
The force of the earth on the ball is towards the center of the Earth, that is, down
all other alternatives are wrong
Answer:
λ= 5.24 × 10 ⁻² nC/cm
Explanation:
Given:
distance r = 4.10 cm = 0.041 m
Electric field intensity E = 2300 N/C
K = 9 x 10 ⁹ Nm²/C
To find λ = linear charge density = ?
Sol:
we know that E= 2Kλ / r
⇒ λ = -E r/2K (-ve sign show the direction toward the wire)
λ = (- 2300 N/C × 0.041 m) / 2 × 9 x 10 ⁹ Nm²/C
λ = 5.24 × 10 ⁻⁹ C/m
λ = 5.24 nC/m = 5.24 nC/100 cm
λ= 5.24 × 10 ⁻² nC/cm
= (3,760 joule/sec) / (4,000 joule/sec)
= 3,760 / 4,000 = 0.94 = 94%
Explanation :
When a person is sliding with constant velocity, the forces that are acting on him are :
(1) Weight, W = mg where g is acceleration due to gravity.
(2) Friction forces acting opposite to the direction of motion.
(3) Normal force.
The forces acting on the person is balanced because the person is sliding with constant velocity.
From figure it is clear that, friction force is balanced by 
and normal is balanced by 
.
