Linear momentum (mass x speed) has to be conserved.
-- Momentum before the jump:
(boy's mass) x (boy's speed) = (25 kg) x (4.0 m/s) = 100 kg-m/s
(cart's mass) x (cart's speed) = (15 kg) x (zero) = zero
Total momentum before the jump: (100 kg-m/s) + (zero) = (100 kg-m/s)
-- Momentum after the jump:
(mass of boy+cart) x (speed of boy+cart) = (40 kg) x (speed)
-- Momentum after the jump = momentum before the jump
(40 kg) x (speed) = 100 kg-m/s
Divide each side by 40 kg:
Speed = (100 kg-m/s) / (40 kg)
<em>Speed = 2.5 m/s</em> (d)
Answer:
92 protons
Explanation:
The mass number is
238
, so the nucleus has <u>238 particles</u> in total, including <u>146 neutrons</u>. So to calculate the number of neutrons we have to subtract: 238 − 146 = 92
Better technology is helping us because we can see more stuff like the microscope we able to make assumptions based on what we saw.