Answer:
7.5 kg
Explanation:
We are given that

Length of plank, l=3 m
Distance of fulcrum from one end of the plank=1 m

We have to find the mass must be on the other end if the plank remains balanced.
Let m be the mass must be on the other end if the plank remains balanced.
In balance condition






Hence, mass 7.5 kg must be on the other end if the plank remains balanced.
Answer:
Specific heat of liquid 
Explanation:
We know in thermal equilibrium :
Loss in heat by iron block = Gain in heat by liquid .
Specific heat of iron = 0.45
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Now , loss in heat by iron block = 
Heat gain by liquid=
Equating both we get :

Answer:
0.34s, 8.5m,31.89m
Explanation:
The above motion defines a projectile motion.
Now the athletes lands on a cliff 30° to the horizontal this means the velocity at that point would be 25m/s cos30°
Now from Newton's law of motion.
The body would be decelerating so,
V = u - gt
Where u is initial velocity and v is final velocity. g is acceleration of free fall due to gravity.
Hence,
V-U/ -g = t
Hence 25cos30 - 25/ -9.8 = 0.34s.
2.Now the length of the jump is defined as the total horizontal distance which is marked off by the horizontal velocity and time taken for take off and landing.
Hence Distance,S = u × t
25 ×0.34 =8.5m.
3. The maximum height is defined that at that point the Final velocity is 0m/s
Now the initial velocity is 25m/s
From Newton's law that;
V2= U2 -2gH; where U and V are initial and final velocity and H is height.
Hence H = V2-U2/-2g
=(0)^2- (25)^2/ -2×9.8
= -625/-19.6 =31.89m
Answer:
Eating food produce locally makes it where big trucks don't have to bring it to the restaurant
Explanation:
When the big trucks drive it they release pollutants into the air so therefore when you get stuff produced locally you don't have the big trucks polluting the air. So therefore it is better for the environment.