One acre is equal to 43560ft².How much is it in m²?
2 answers:
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Answer:
The coefficient of kinetic friction is 0.13
Explanation:
Newton's second law states that the acceleration of an object is proportional to the net force on it, the factor of proportionality is the mass. So, we can express that law mathematically as:
(1)
With F the net force, m the mass and a the acceleration of the object. In our case we're interested on what's happening to the sled, then we have to analyze the forces on it, those forces are the weight and the normal force on the vertical direction and the pulling force and frictional force in the horizontal direction. So, because (1) is a vector equation we can express that in their vertical (y) and horizontal (x) components:
(2)
(3)
On y we have that the acceleration is zero because the sled is not moving upward or downward, remember that the net force on y is the weight (W) pointing downward and the normal force pointing upward:
Following the convention that positive is upward and negative downward, W=mg=(755)(-9.81):
(4)
Now on the x direction we have the sum of the forces is the pulling force (T) and friction force (f)
Choosing the direction where the horse is pulling F=1988N and the acceleration should be positive too, then:
The negative sign means it's in the opposite direction the horse is pulling
The frictional force is related with the coefficient of kinetic friction in the next way:
with μk the coefficient of kinetic friction, and n the normal force that we already found on (4), so we simply solve the last equation for μk:
Answer:
(a) Most reactive Metal B
Metal D
Metal A
Least reactive Metal C
(b) (i) Bubbles should form very slowly
(ii) No reaction takes place
Explanation:
(a) The given metals arranged in their order of reactivity are;
Most reactive Metal B
Metal D
Metal A
Least reactive Metal C
The other of reactivity is based on the nature of their reactivity of the metals in air
(b) (i) Based on the reactivity of the metals in air, whereby metal A reacts very slowly and an oxide is formed, we have that, based on the reactivity of the metal A, when mixed with dilute hydrochloric acid, bubbles should form very slowly
(ii) Similarly, given that metal C is unreactive, we have that when small pieces of metal C are added to dilute hydrochloric acid, no reaction takes place.
Answer:
t = 3.29 seconds
Explanation:
It is given that,
Height of the Eiffel tower is 60 m
Initial speed of a euro, u = 2 m/s
It will move under the action of gravity in the downward direction. Firstly, we can find the final velocity as follows :
Let t is the time taken by the euro to hit the ground. It can be calculated as :
Hence, it will take 3.29 seconds to hit the ground.