Answer:
a) Andrea's initial momentum, 200 kg m/s
b) Andrea's final momentum, 0
c) Impulse, = - 200 Ns
d) The force that the seat belt exerts on Andrea, - 400 N
Explanation:
Given data,
The initial velocity of the car is, u = 40 m/s
The mass of Andrea, m = 50 kg
The time period of deceleration, a = 0.5 s
The final velocity of the car, v = 0
a) Andrea's initial momentum,
p = mu
= 50 x 40
= 200 kg m/s
b) Andrea's final momentum
P = mv
= 50 x 0
= 0 kg m/s
c) Impulse
I = mv - mu
= 0 - 200
= - 200 Ns
The negative sign indicated that the momentum is decreased.
d) The force that the seat belt exerts on Andrea
F = (mv - mu)t
= (0 - 200) / 0.5
= - 400 Ns
Hence,the force that the seat belt exerts on Andrea is, - 400 N
Answer:
1/ As a metal has higher melting point than a nonmetal has, we can guess that sample A is a metal.
2/ The melting point is over 1000 gradius Celcius: 1083 - it's not a low value. And as the sample conducts heat, it is not the element of period N3 in the periodic table, because elements in period 3 do not conduct electricity.
Explanation:
I can not see what the questions 2-3 in your picture is. I answered the question above the table: What can the student conclude about thenidentity of Sample A.
PE=mgh=150kg*9.8m/c² *50m=73500 J
W=F*d=mgd = 2.5*9.8*3.0 = 73.7J
W=mgh=68.0*7.62*9.8 =50.78 J
150 lb = 68.0 kg
25 ft = 7.62m
