Answer:
Optimists generally approach life with a positive outlook, while pessimists tend to expect the worst. Optimists go into new situations with high expectations, while pessimists keep low expectations to prepare for negative outcomes
Explanation: Optimists generally approach life with a positive outlook, while pessimists tend to expect the worst. Optimists go into new situations with high expectations, while pessimists keep low expectations to prepare for negative outcomes
Answer:
The object accelerates downward at 4 m/s² since the tension on the rope is less than weight of the object.
Explanation:
Given;
mass of the object, m = 2 kg
weigh of the object, W = 20 N
tension on the rope, T = 12 N
The acceleration of the object is calculated by applying Newton's second law of motion as follows;
T = F + W
T = ma + W
ma = T - W
(the negative sign indicates deceleration of the object)
The object accelerates downward at 4 m/s² since the tension on the rope is less than weight of the object.
Answer:
v = wavelength * frequency
frequency = 5200 m/s / .2 m = 26000 / sec
20,000 / sec is optimistic for the upper frequency of human hearing
So 26,000 is above the hearing range for human ears
Answer:
(a) 
(b) 
(c) K.E. = 21.168 J
(d) 
Explanation:
Given:
- mass of a block, M = 3.6 kg
- initial velocity of the block,

- constant downward acceleration,

That a constant upward acceleration of
is applied in the presence of gravity.
∴
- height through which the block falls, d = 4.2 m
(a)
Force by the cord on the block,



∴Work by the cord on the block,


We take -ve sign because the direction of force and the displacement are opposite to each other.

(b)
Force on the block due to gravity:

∵the gravity is naturally a constant and we cannot change it


∴Work by the gravity on the block,



(c)
Kinetic energy of the block will be equal to the net work done i.e. sum of the two works.
mathematically:


K.E. = 21.168 J
(d)
From the equation of motion:

putting the respective values:

is the speed when the block has fallen 4.2 meters.