Question 856:

• JAMB 1997

A body of mass 2kg moving vertically upwards has its velocity increased uniformly from 10ms^-1 to 40ms^-1 in 4s. Neglecting air resistance, calculate the upward vertical force acting on the body.[g = 10 ms^-1]

A. 15N
B. 20N
C. 35N
D. 45N

Question 857:

• JAMB 1997

A planet has mass m₁ and is at a distance r, from the sun. A second planet has mass m₂ = 10m₁ and at a distance of r₂ = 2r₁ from the sun. Determine the ratio of the gravitational force experienced by the planets.

A. 1 : 5
B. 2 : 5
C. 3 : 5
D. 4 : 5

Question 858:

• JAMB 1997

An object of mass 100g projected vertically upwards from the ground level has a velocity of 20ms^-1 at a height of 10m. calculate its initial kinetic energy at the ground level.[g = 10ms^-2, neglect air resistance]

A. 10 J
B. 20 J
C. 30 J
D. 50 J

Question 859:

• JAMB 1997

An electric water pump rate 1.5 kW, lifts 200kg of water through a vertical height of 6 meters in 10 seconds. What is the efficiency of the pump? [g = 10ms-2, neglecting air resistance]

A. 90.0%
B. 85.0%
C. 80.0%
D. 65.0%

Question 860:

• JAMB 1997

A load of 20N on a wire of cross-sectional area 8 x 10^-7m², produces an extension of 10m². calculate Young's modulus for the material of the wire if its length is 3m

A. 7.0 x 10¹¹Nm^-2
B. 7.5 x 10¹¹Nm^-2
C. 8.5 x 10¹¹Nm^-2
D. 9.0 x 10¹¹Nm^-2