Here we know that mass of the person is 90 kg
His weight is given as 30 lbf
so here we can convert it into Newton as we know that
1 lbf = 4.45 N
Now from above conversion

now we can use this to find the gravity at this height



now we know that with height gravity varies as



so above is the height from the surface of earth
Answer:
(a). The initial velocity is 28.58m/s
(b). The speed when touching the ground is 33.3m/s.
Explanation:
The equations governing the position of the projectile are


where
is the initial velocity.
(a).
When the projectile hits the 50m mark,
; therefore,

solving for
we get:

Thus, the projectile must hit the 50m mark in 1.75s, and this condition demands from equation (1) that

which gives

(b).
The horizontal velocity remains unchanged just before the projectile touches the ground because gravity acts only along the vertical direction; therefore,

the vertical component of the velocity is

which gives a speed
of


Answer:
B
Explanation:
Acceleration = rate of change in velocity
a = (21-12)/(0.45) = 20cm/s^2
Answer: 
Explanation:
The acceleration of the motorcycle is given by Newton's second law:

where
F = 1295 N is the force applied to the motorcycle
m = 350 kg is the mass of the motorbike
a is the acceleration
By substituting the numbers into the formula, we find

Answer:
<em>Digital clock is the most precised one</em>
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Explanation: